Photography of the Invisible World

[UV] BBC How to Grow a Planet - The Hidden World of UV (III)

2012-02-13T20:55:00.006+01:00

I had previously announced here my contribution to the BBC2 new three episode series "How to Grow a Planet" (renamed from "Green Planet") which will be presented by Professor Iain Stewart.

So Episode 2 "The Power of Flowers" will be broadcast at 9pm GMT on BBC2 (and BBC HD) on Tuesdays 14 February 2012 in the UK (and the following Friday in Scotland at the same time) and a bit later will also be visible through BBC's iPlayer.

Beware: It is only permissible to play this clip, if you are located in England, Scotland or Ireland

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] White Primrose (Primula) in deep ultraviolet light

2012-02-12T16:14:00.006+01:00

When I passed by my friends' flower shop and saw he had some primroses (primulas), I wanted to see, if there would be some UV structure visible if shot in reflected ultraviolet light. This one is a bread form, all white and filled.

[click on image to see a larger one]

These UV images here also uses my standardized false UV color normal + high intensity palette:

Well and indeed there gets something visible...

VIS:

UV:

Now I was wondering about the contribution of the shorter wave, deeper UV sub-bands (as I call them). Here the results of using the plain Baader U2 filter (left) versus that same filter stacked with a filter that cuts all below 360nm, but passes all above (right)

It gets pretty obvious, that these shorter UV wavelengths are able to differentiate and make more structures visible. Here the red and especially green channel response play an important role.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] BBC Green Planet Series - The Science of Plants - How to Grow a Planet (II)

2012-02-07T11:42:00.003+01:00

I had previously announced here my contribution to the BBC2 new three episode series "How to Grow a Planet" (renamed from "Green Planet") which will be presented by Professor Iain Stewart.

It has now been published that the series will be broadcast at 9pm GMT on BBC2 (and BBC HD) on Tuesdays 7, 14 and 21 February 2012 in the UK (and the following Friday in Scotland at the same time) and a bit later will also be visible through BBC's iPlayer.

The official BBC episode list is here with previews and my part will be shown in episode 2 on Feb 14, 9pm GMT.

This is the official broadcast card:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS, IR] Lyman Alpha deep UV lenses

2012-02-03T11:00:00.012+01:00

Well, an old collectors rule is "everything comes to him who can wait" - that it would be 16 years from when I first learned about that lens and personally had contact with its inventor Richard Nye, I had not really expected.

Now a few days ago I was able to acquire three prototypes of those lenses, made 1992, which came from the estate of the inventor, Richard Nye, who has passed in 2007, then 77 years old. His company, Nye Optical, La Mesa CA, unfortunately does not exist anymore.

So, the scientific lenses he invented and custom made were for deep UV recording (capable to work beyond 200nm, especially made to record the 121nm Lyman alpha lines, hence the name - only in vacuum or nitrogen atmosphere of course), but having no chromatic aberration also in VIS and IR. It is a catoptric (reflex) Cassegrain design, which came in f2.8/200mm and f1.1/90mm versions for full format cameras (43mm image circle), but also for intensifier tubes and video cameras (25mm image circle), with focusing from 250mm to infinity and some adjustable 50mm resp. 18mm back focal length.

[click on image to see a larger one]

Inside the aluminum housing resides an about 25mm (1") thick quartz (ZERODUR most likely) mirror block, front aluminized plus a secondary mirror (most likely made of the same material) held by an adjustable metal "spider" in front of that first one. Quite built like a small 90mm diameter Cassegrain astronomical telescope.

DOF at one (1) meter (3ft) is as thin as a razor blade when using the Lyman Alpha f1.1/90mm lens and that doughnut shaped bokeh etc. makes it fun to use. So here a first visible light shot:

Additionally a short test video I shot using that lens:

which shows its dreamlike/surreal/ethereal rendering of images.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Lichen in reflected ultraviolet light III

2012-01-30T20:42:00.003+01:00

Today more about Lichen shots in visible and ultraviolet light, especially how damaged or dead lichen look like.

[click on image to see a larger one]

These UV images here also uses my standardized false UV color normal + high intensity palette:

Damaged/dead Lichen

Fungus overgrown:

VIS:

UV:

Dead Lichen (bottom of picture):

VIS:

UV:

So it gets clear, that the UV image reveals living lichen, by its UV reflection, in the case of these species here at around 380nm.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Lichen in reflected ultraviolet light II

2012-01-30T17:20:00.004+01:00

Today more about Lichen shots in visible and ultraviolet light.

[click on image to see a larger one]

These UV images here also uses my standardized false UV color normal + high intensity palette:

Lichen growing on a brownstone rock

VIS:

UV:

UV - different filtering:

Here this lichen specimen reflects UV at around 380nm. Interesting to note, how much details these UV shots reveals!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Transmittance of the Minolta TC f4 135mm Triplet Lens

2012-01-28T06:46:00.008+01:00

I tested some bellows lens heads the other day and the (expected) surprise was, how well that older and overlooked Minolta TC f4/135mm bellows lens head performed (teal and pink line), nearly identical to the Noflexar 35mm (red line; only about 0.2 stops less at 365nm). [I'm not sure if later made models may have the same good transmittance, as the coating may have been changed]

[click on image to see a larger one]

Here now a quick photographic test of that lens, which shows quite some focus shift in UV, the triplet lens design it is.

The micro structure that gets visible on the left petals looks promising, so quite a useful lens I have to say. Btw. it also comes mounted on a focusing helicoid for Minolta mount, sold under the same name, but the lens head can be unscrewed as it has a Leica thread mount (M39 x 26tpi) which is the standard enlarger lens mount.

Outside tests will have to be performed to see if it is free of hotspots, how free of flare it is etc.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Transmittance of some Bellows Lens Heads

2012-01-28T06:27:00.006+01:00

I conducted a test today to measure the UV transmittance of some older manual bellows lens heads I have here.

Be reminded that this is only a test of the suitable UV transmittance, not of other important parameters for UV photography (sharpness, contrast, freedom of flare or hotspots etc.)

Of course the well known Novoflex Noflexar 35mm has been used as a reference, as it stands out as a very well UV transmitting lens. The (expected) surprise was, how well that older and overlooked Minolta TC f4/135mm perfomed, nearly identical to the Noflexar (only about 0.2 stops less at 365nm).

I will show its photographic performance in a separate test later.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Lichen in reflected ultraviolet light

2012-01-25T23:08:00.003+01:00

Today about Lichen shots in visible and ultraviolet light.

[click on image to see a larger one]

These UV images here also uses my standardized false UV color normal + high intensity palette:

Lichen on oak tree

VIS:

UV:

Lichen on another tree

VIS:

UV:

Interesting to note, how much details these UV shots reveals!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

"Kingdom of Plants" Sir David Attenborough on Kew Gardens in 3D stereo

2012-01-05T11:15:00.014+01:00

There will be a new forthcoming three episode series airing in Spring 2012 narrated and written by Sir David Attenborough, which mainly is about Kew Gardens in the UK (working title was "Kew 3D"). It was produced by Atlantic Productions (Colossus Productions) for SKY 3D TV and directed by Martin Williams. Sir David Attenborough will be the presenter and guide through the episodes.

It has been filmed in HDTV 3D stereo mainly intended to be aired in SKY's 3D channel.

According to imdb it will be released May 6, 2012

Reference: Kingdom of Plants on imdb

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] BBC Green Planet Series - The Science of Plants - How to Grow a Planet

2011-12-29T20:43:00.011+01:00

There will be a new major BBC 3x 60min series, produced by BBC Scotland which will be aired on BBC TWO most likely in spring 2012. The current working title of the series is "Green Planet" and it will be presented by geologist and Professor Iain Stewart.

[click on image to see a larger one]

(c) BBC London

My UV part will be shown in the "The Science of Plants" section. So what you'll see will be some of my recent work, for instance Rudbeckia

as well as Hemerocallis, Zinna and Bidens, just to name some.

As soon as I know more details or have the schedule when this will be aired on BBC TWO, I'll let it know here.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Hippeastrum (Amaryllis) details in ultraviolet light

2011-12-25T16:33:00.006+01:00

A good friend sent a wonderful Christmas Bouquet which also included deep red Hippeastrum (Amaryllis) blossoms, I have already published about it here on my BLOG. Now UV closeups of that one, shot using a UV-Planar 60mm and my Lumix GH1 UVIR. Filter used for the reflected UV shots was the Baader-U filter and a modified high power Xenon flash served as light source.

[click on image to see a larger one]

Closeup including stigma and stamen:

the petal surface:

an finally the glowing stigma:

Doesn't that look like "pure amethyst"?

Impressive how much such a beautiful Christmas Gift may reveal, even if it is invisible to our human eyes...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Christmas Bouquet

2011-12-24T12:01:00.000+01:00

A good friend sent a wonderful Christmas Bouquet - so here it is as it looks like in reflected ultraviolet light. It was shot using my Lumix GH1 UVIR and a Noflexar 35mm lens. Filter used for the UV shot was the Baader-U filter and a modified high power Xenon flash was the light source used.

[click on image to see a larger one]

So I wish everyone Merry Christmas and a Happy New Year!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Hippeastrum (Amaryllis)

2011-12-23T19:30:00.004+01:00

This is about Hippeastrum or as it is called here, Amaryllis, usually sold around Christmas time. It was shot using my Lumix GH1 UVIR and a Cerco 94mm lens. Filter used for the UV shot was the Baader-U filter and a modified high power Xenon flash served as a light source.

[click on image to see a larger one]

UV:

VIS:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV,VIS,IR] Staeble Lineogon f3.5 / 35mm wide angle lens for reflected UV

2011-11-25T18:46:00.005+01:00

Here some test results using the Staeble Lineogon 3.5/35mm lens for reflected UV photography, as well as for IR after having done some successful transmittance tests as shown here on my BLOG

VIS:

UV:

VIS-UV differential:

IR:

VIS-IR differential:

UV-IR differential:

[please ignore the shadow image in the last three images caused by ND+IR stacked filters, this is unrelated to the lens performance]

In summary one could say that the lens performs quite well; there is some focus shift, but rather small. No wonder actually, since Stable was the subcontractor of Novoflex, so the Noflexar 3.5/35mm and the Lineogon 3.5/35mm share the same optics based on my research. The mechanics are different though, as the Lineogon has a quite smaller barrel and also lacks the close-up focusing mechanism teh Noflexar is so famous for. It also has a M39 thread mount, but not a Leica register, as it once was made for the Braun PAXETTE camera, having a 44.0mm register.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Tested transmittance of eight 35mm wide angle lenses for reflected UV

2011-11-25T17:54:00.007+01:00

I conducted a test today to measure the UV transmittance of some older manual focus lenses I had sitting around, all f = 35mm and all having either M39mm or M42mm thread mount, so may easily be adapted onto modern DSLR's, if their back focal length fits the camera register.

Be reminded that this is only a test of the suitable UV transmittance, not of other important parameters for UV photography (sharpness, contrast, freedom of flare or hotspots etc.)

Of course the well known Novoflex Noflexar 35mm stands out as a very well transmitting lens and it is actually not a surprise that the Staeble Lineogon does about equally well - it is the same optics inside as Novoflex subcontracted to the German company Staeble to design their optics, which my own research concluded. Be reminded that the Lineogon was made for the PAXETTE camera with M39 thread mount, but for a 44mm register (so is NOT Leica compatible, but helps to adapt as it allows for 15mm more space).

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Baader-U versus Andrea-U filter

2011-11-18T16:40:00.005+01:00

Noticed that I haven't published a test of the 2" Andrea-U filter I had bought beginning of May 2011, so here it is. It is sold under the moniker "Andrea-U filter", like Baader sells his as "Venus-Filter".

A first comparison of the uncoated 2.05mm thick Andrea-U filter with the Baader-U2 filter (2", new type) brought the following results:

I) Transmittance

A spectral scan results in the following transmittance graph (@ zero and 45 degrees angle of light):

The results of the Baader-U2 filter is also shown, to be able to compare both filters. Andrea-U has some leakage into the violet/deep blue to about 410nm, but there is no sign of IR-leakage (up to 850nm).

II) Reflected UV Photography Test
(using Lumix GH1-UVIR, Cerco 94mm lens; Rudbeckia hirta as a target, Xenon flash; identical settings for aperture, flash energy, exposure)

- leftmost: using Baader-U2 filter, using my standardized "standard false UV color palette"
- rightmost: using Andrea-U filter, using my standardized "standard false UV color palette"
- middle: using Andrea-U filter, using a "special false UV color palette" (developed to match the results when using the Baader-U2 filter)

The resulting Andrea-U image has an exposure which is about 1/4 stop less that that of the Baader-U2. There is no sign of IR-leakage (up to 850nm); the somewhat warmer tone of the middle image was caused by the special palette used. All images were processed identically otherwise.

III) Summary

The Andrea-U filter is mechanically well made (the description is printed on foil and taped on the rim, which might eventually come off after long use - I would have preferred it printed or engraved of the metal, but that would certainly have increased cost).

Personally I would rate it a quite useful filter for the 375nm range, especially if used with older "normal" UV transmitting lenses since in the 375-400nm range it has a higher transmittance as the Baader-U2 filter (25% higher = 0.5EV at 390nm).

Other than that I will refrain from a further discussion here, as the results are pretty self-explanatory.

.

[UV, VIS, IR] Canon f3.5 / 25mm - Topogon clone

2011-11-08T21:12:00.004+01:00

Also took a few shots today on a dull+gray day using another famous and quite rare rangefinder lens, a Canon f3.5 / 25mm Topogon clone designed by Mukai Jirō in 1956 with Leica thread mount (LTM 39mm x 26tpi) with a diagonal angle of view of 82° (on full format). My friend Marco Cavina has a very good article about those lenses based on the TOPOGON design HERE .

These Topogon clone lenses are all successors of the famous HYPERGON lens designed by Emil von Hoegh around 1900.

Shots were done @f8 and ISO640 on my Lumix GH1 UVIR.

[click on image to see a larger one]

Left VIS, right UV (bw) 100% center crop:

Left VIS, right IR (bw) 100% center crop:

Now color differentials (full format) to make focus shift visible:

VIS-UV:

VIS-IR:

IR-UV:

As you see, there is some small focus shift (UV and especially IR image show slight back focus), but nothing dramatical (focus was not touched, the shift could be calibrated of course). Interestingly enough, there is only a very small shift between UV and IR (a 695LP filter was used), but overall the IR shift is much larger than the nearly neglectable one for UV (Baader-U filter was used).

In terms of exposure, the one for UV was -7.7EV as compared to the VIS shot, whereas the one for IR was the same as for VIS. All shots (VIS, UV, IR) needed identical exposure correction (+2/3 stop) for a proper exposure using A mode.

Here now closeups using one of my last Rudbeckias. Distance between lens and flower was about 100mm (using a thin helicoid for closer focusing, as with most rangefinder lenses, the closest focusing distance is one meter):

VIS:

UV:

IR:

Not that bad actually also that lens ;)

That Canon 3.5/25mm transmits UV to about 350nm, but the UV shot above was taken using the calibration of a flat transmitting quartz fluorite lens, to show the effect also in the resulting color. A color calibration could have been done also for that lens.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS, IR] Orion-15 f6 / 28mm - Topogon clone

2011-11-08T20:45:00.012+01:00

Took a few shots today on a dull+gray day using a very small and lightweight russian rangefinder lens, an Orion-15 f6/28mm Topogon clone with Leica thread mount (LTM 39mm x 26tpi) with a diagonal angle of view of 75° (on full format). My friend Marco Cavina has a very good article about that lens HERE including quite surprising photographic comparisons with much more expensive Leica lenses.

These Topogon clone lenses are all successors of the famous HYPERGON lens designed by Emil von Hoegh around 1900.

Shots were done @f8 and ISO640 on my Lumix GH1 UVIR.

[click on image to see a larger one]

Left VIS, right UV (bw) 100% center crop:

Left VIS, right IR (bw) 100% center crop:

Now color differentials (full format) to make focus shift visible:

VIS-UV:

VIS-IR:

IR-UV:

As you see, there is some focus shift (UV + IR image show slight back focus), but nothing dramatical (focus was not touched, the shift could be calibrated of course). Interestingly enough, there is only a very small shift between UV and IR (a 695LP filter was used), but overall the IR shift is larger than that for UV (Baader-U filter was used).

In terms of exposure, the one for UV was -7.3EV as compared to the VIS shot, whereas the one for IR was the same as for VIS. All shots (VIS, UV, IR) needed identical exposure correction (+2/3 stop) for a proper exposure using A mode.

Here now closeups using one of my last Rudbeckias. Distance between lens and flower was about 150mm (using a thin helicoid for closer focusing, as with most rangefinder lenses, the closest focusing distance is one meter):

VIS:

UV:

IR:

Not that bad actually ;)

That Orion-15 transmits UV to about 350nm, but the UV shot above was taken using the calibration of a flat transmitting quartz fluorite lens, to show the effect also in the resulting color. A color calibration could have been done also for that lens.

A downside should be mentioned: that lens has a 40.5mm deep set front filter thread that does not allow step rings to be mounted, so some clever idea how to attach filters is called for...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS, IR] Carl Zeiss Jena Lamegon 38mm

2011-10-28T21:19:00.006+02:00

I have this lens since quite a while but never really thought it would be useful for UV or IR due to its complex lens design incorporating lots of glass elements and a few cemented ones, based on the famous Biogon design of Dr Bertele. But well, I'm too much a curious engineer, so while I was digging through lenses, I thought, I should convert it and give it a chance...

Actually that lens design was developed and used long time as their (former GDR) best wide angle lens, used for their "Reihenmesskammer" for aerial reconnaissance. This lens here is a derivative of its larger brother, with an reduced image angle and most likely a symmetrical 8e/4g design.

Here is a technical article of my friend Marco Cavina, that covers such ultra wide angles nicely with lots of images and diagrams as well as showing never finished prototypes.

[click on image to see a larger one]

UV-VIS differential:

Focus shift? Very small and neglectable!

VIS:

UV:

Closeups:

VIS:

UV:

IR:

well, no complaints I would say..

[unfortunately also that flower has already started its decline, which UV shots reveal so easily...]

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[IR, VIS] Hypergon 26mm ultra wide angle also for IR

2011-10-19T12:10:00.004+02:00

More today about that ultra wide angle large format HYPERGON lens I have published before.

It turned out that it seems to be a quite useful lens for VIS and now also IR on my Panasonic GH1/2 camera(s), although it has quite some focus shift also in IR (expected from that simple design). The focal length has been confirmed by further measurements to be around 25 - 26mm, so let's stay with 26mm.

Here is a technical article of my friend Marco Cavina, that covers such ultra wide angles nicely with lots of images and diagrams as well as showing never finished prototypes.

Transmission:

[note: measured at f11]

Now more photographic results.... [click on image to see a larger one]

VIS/IR:

Detail:

Quite acceptable also for IR I'd say, even if there is some loss in sharpness and contrast...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Hypergon 26mm ultra wide angle

2011-10-12T22:08:00.013+02:00

I found and adapted a previously unknown (in that focal length) ultra wide angle large format lens, obviously a Hypergon design, which Emil von Höegh invented around 1900 for the GOERZ company [he also invented the famous DAGOR lens for them] which was later taken over by ZEISS. Based on that Hypergon design, Robert Richter later in 1934 developed the famous TOPOGON lens for ZEISS, which became the classic aerial imaging lens for quite some time. The earlier Hypergon I have here was made approx. 1950 I would guess with a diagonal angle of view of about 120° (on its designed format of about 145mm image circle).

It turned out that it seems to be a quite useful lens for VIS and UV on my Panasonic GH1/2 camera(s), although it has quite some focus shift in UV (expected from that simple design). The focal length is an estimate, it is somewhere between 24 - 26mm from my measurements. I show the lens aberrations in the following screenshot (scaled to fit a Lumix sensor, hence smaller used image angle and object at infinity; for an f11 aperture, which is the optimum for that lens):

Here is a technical article of my friend Marco Cavina, that covers such ultra wide angles nicely with lots of images and diagrams as well as showing never finished prototypes.

Now some photographic results.... [click on image to see a larger one]

VIS/UV:

Transmission:

[note: measured at f11]

These were also shot using it:

and despite the well known aberrations, using it results in quite useful images, also for visible light photography, thanks to its good contrast and sharpness:

and its good flare resistance:

Quite a nice find I'd say...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Rudbeckia fulgida opening up III

2011-09-25T08:44:00.003+02:00

More about the development of that Rudbeckia fulgida flower which is in the process of opening, so enjoy more shots in visible and ultraviolet light.

[click on image to see a larger one]

These UV images here also uses my standardized false UV color normal + high intensity palette:

and a few hours later:

Interesting to note, how these different UV reflection patterns further develop in the process of that flower maturing - that was one of the ideas behind performing that study.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Rudbeckia fulgida opening up II

2011-09-23T17:21:00.004+02:00

and some hours later:

Interesting to note, how these different UV reflection pattern develop in the process of that flower maturing - that was one of the ideas behind performing that study.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Rudbeckia fulgida opening up

2011-09-19T18:25:00.002+02:00

Another Rudbeckia fulgida flower is in the process of opening, so enjoy shots in visible and ultraviolet light.

[click on image to see a larger one]

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] Rudbeckia fulgida in crosseyed stereo

2011-09-18T20:03:00.003+02:00

More from Indian Summer that has started here. A few days ago a beautiful Rudbeckia fulgida flower that had opened up, so enjoy a couple of crosseyed stereo shots in visible and ultraviolet light.

[click on image to see a larger one]

Lens used for that shot was also that old industrial lens, I am currently testing. Quite some focus shift it has, but quite useful it is nevertheless.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] Rudbeckia hirta in crosseyed stereo

2011-09-12T15:51:00.005+02:00

Indian summer has started and some flower expose the late bloom to the sun. This Rudbeckia hirta did so too, so enjoy a couple of crosseyed stereo shots in visible and ultraviolet light.

[click on image to see a larger one]

Lens used for that shot was an old industrial lens, I am currently testing. Quite some focus shift it has, but quite useful nevertheless.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] How flowers stand out in UV - ultraviolet HDTV video

2011-09-04T20:56:00.004+02:00

Today more about UV videos, here a video shot at Hermannshof park, Weinheim Germany. It shows how flower found a way during evolution to really makes them stand out in UV.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Rudbeckia fulgida meets Zeiss UV-Planar 60mm

2011-09-02T20:59:00.006+02:00

Shots from our wonderful Hermanshof Park here in Weinheim, of a Rudbeckia fulgida variant shot, using a Zeiss UV-Planar 4/60mm lens and Baader-U filter for the UV shot.

[click on image to see a larger one]

fully open at f4:

stopped down to f5.6:

Here now UV-VIS differentials on the right side.

fully open at f4:

stopped down to f5.6:

This lens is so sharp, already fully open, so stopping down is only needed to control the DOF (depth of field).

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] Late Summer's "Grand Finale" - Zeiss UV-Planar 60mm

2011-09-02T19:47:00.007+02:00

Today summer came back and flashed his intensive golden rays over our wonderful Hermanshof Park here in Weinheim, so I grabbed my system and took a few shots. Without more ado, have a look in VIS and UV...

[click on image to see a larger one]

[the yellow flower is Helianthus tuberosus and the violet flower is an Aster type]

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Do flowers have an ultraviolet aura?

2011-08-22T02:20:00.002+02:00

Today something artistic, hence the rhetoric title question. So for your hopefully viewing pleasure without any technical or scientific ado, here my images...

[click on image to see a larger one]

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Mirabilis jalapa in reflected ultraviolet

2011-08-11T01:13:00.005+02:00

Reflected UV image (mainly at 333nm):

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Mirabilis jalapa UV induced fluorescent pollen

2011-08-10T18:04:00.010+02:00

Today about a very interesting flower, Mirabilis jalapa. This flower, also called "four-a-clock" uses a very special technique to enhance the visibility to its pollinators, in that case hawkmoths, that are active when the light gets dimmer, i.e. in the late afternoon and evening hours (hence that name). Scientists have found out, that the pollen of this flower is highly fluorescent i.e. ultraviolet light, which is proportionally more present in early morning and later afternoon hours, is "used" and downconverted to visible light (i.e. fluorescence light) according to Stokes Law. So this down converted light overlays the visible light present and so enhances the visibility to its pollinators. The yellow parts of the flower petals also exhibit green fluorescence, but to lesser extent and in green light. Now let's see how that looks like...

[click on image to see a larger one]

Left: visible image; right: UV induced visible light pollen image:

It gets strikingly visible, how intense this effect actually is!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Clivia miniata flower through a quartz soft focus lens

2011-08-02T00:25:00.003+02:00

Here again a shot of a Clivia miniata flower as shown in a previous entry here. But this time it is not about technical aspects, but how special such a soft focus shot in reflected ultraviolet light looks like.

[click on image to see a larger one]

Here a true soft focus lens was used, which gets easily visible for the trained eye. Unfortunately an art style which has gotten somewhat lost. But a few still hold on to that slow form of photography to bring out the "light from within"...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Clivia miniata flower in ultraviolet light

2011-08-01T18:26:00.009+02:00

Here shots of a Clivia miniata flower. This flower exhibits some different longer wave UV reflection, in blue/violet color corresponding to a about 385-395nm UV reflection in the deep center and whitish color i.e. UV reflection around 370-375nm from the middle to the petal tip (cf my false color UV palette).

[click on image to see a larger one]

This UV image here also uses my Standardized false UV color normal + high intensity palette:

UV image:

VIS image:

A spectrometric confirmation of these above mentioned assumptions concerning the reflectivity of this flower petal is here:

The max. reflection of the whitish tip in UV using my standardized false UV color palette is around 373nm and the deeper parts of the petal which looks violet has its maximum at 389nm which both confirms the expectations mentioned above.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] foraging bee on Campanula - ultraviolet HDTV video

2011-07-29T03:00:00.002+02:00

Today more about UV videos, here shots from Hermannshof park of a Campanula persicifolia flower. This flower exhibit a long wave UV reflection and very light UV pattern, in blue/violet color corresponding to a about 395nm UV reflection (cf my false color UV palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video of Campanula:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] foraging bee on Malva - ultraviolet HDTV video

2011-07-29T02:48:00.004+02:00

Today more about UV videos, here shots from Hermannshof park of a Malva moschata flower. This flower exhibit a long wave UV reflection and very light UV pattern, in blue/violet color corresponding to a about 390nm UV reflection (cf my false color UV palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video of Malva:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Ant on Zinnia with deep UV reflection - ultraviolet HDTV video

2011-07-29T02:12:00.004+02:00

Today more about UV videos, here shots from Hermannshof park of Zinnia flowers from Mexico. This flower exhibits a very prominent and very deep into UV reaching bullseye pattern, here represented by green - yellow colors corresponding to a 340 - 360nm UV reflection (cf my false color UV palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video of deep UV reflecting Zinnia with ant:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Foraging bees on Echinops - ultraviolet HDTV video

2011-07-29T01:53:00.003+02:00

Today more about UV videos, here shots from Hermannshof park of a Echinops flower. This flower exhibit only a long wave UV reflection and very light UV pattern, in blue/violet color corresponding to a about 390nm reflection (cf my false color UV palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video of Echinops:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Helianthus tuberosus and foraging bee - ultraviolet video

2011-07-27T09:55:00.003+02:00

Today more about UV videos, here shots from Hermannshof park of a Helianthus tuberosus flower. These flowers exhibit a quite prominent bullseye pattern, in yellow colors corresponding to a 360nm UV reflection (cf my false color UV palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video of Helianthus tuberosus:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Gaillardia with foraging Bumble Bee - ultraviolet HDTV video

2011-07-27T09:46:00.007+02:00

Today more about UV videos, here shots from Hermannshof park of a Gaillardia aristata flower. These flowers exhibit a hidden, but very prominent bullseye pattern, in yellow colors corresponding to an about 360 - 370nm UV reflection (cf my false color UV palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video of Gaillardia:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Zinnia with deep UV reflection pattern - ultraviolet HDTV video

2011-07-26T21:29:00.007+02:00

Today more about UV videos, here shots from Hermannshof park of Zinnia flowers from Mexico (I published about them here earlier). These flowers exhibit a very prominent and very deep into UV reaching bullseye pattern, here represented by green - yellow colors corresponding to an about 340 - 360nm UV reflection (cf my false color UV palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video of deep UV reflecting Zinnias:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Foraging bee on Zinnia flower in UV - ultraviolet HDTV video

2011-07-26T21:20:00.006+02:00

Today more about UV videos, here shots from Hermannshof park of a foraging bee on a Zinnia flower from Mexico (I published about them here earlier. This flower exhibits a very prominent and deep into UV reaching bullseye pattern with some grayish reflection, corresponding to an about 370nm UV reflection (cf my standardized false UV color palette), which gets nicely visible in this HDTV video.

This video here also uses my Standardized false UV color normal + high intensity palette:

UV video with foraging bee on a Zinnia:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Fly and Bumble Bee on Rudbeckia flower - ultraviolet HDTV video

2011-07-26T14:24:00.004+02:00

Today more about UV videos, again using a Rudbeckia fulgida flower, but this time with two guests, an inspecting fly and a foraging Bumble Bee. This flower exhibit a very prominent UV bullseye pattern, which gets nicely visible in this HDTV video; before I had shown UV video snippets in May 2009 as a preparation for the filming of BBC's "Richard Hammonds Invisible Worlds".

These videos here also use my Standardized false UV color normal + high intensity palette:

UV video with Fly on Rudbeckia:

UV video with Bumble Bee on Rudbeckia:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] street scene in reflected UV ultraviolet - HDTV video

2011-07-25T23:12:00.009+02:00

Today again about UV videos, which I had already presented here and much earlier in May 2009 here. This here is a street scene as seen from my balcony in reflected ultraviolet light (320-390nm). The houses show interesting UV reflections, which I would like to present here in HDTV video form.

This video also uses my Standardized false UV color normal + high intensity palette:

UV video:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Rudbeckia flower - reflected UV ultraviolet HDTV video

2011-07-25T22:59:00.009+02:00

Today about UV videos, here using a Rudbeckia fulgida and R. hirta as examples. These flowers exhibit a very prominent UV bullseye pattern, which I would like to present here as a HDTV video; before I had shown UV video snippets in May 2009 as a preparation for the filming of BBC's "Richard Hammonds Invisible Worlds".

These videos here also use my Standardized false UV color normal + high intensity palette:

UV videos:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, FL, VIS, NIR] A very special Zinnia from Mexico

2011-07-22T10:50:00.005+02:00

Today about a very special Zinna flower from Mexico, the boss of our most beautiful park Hermannshof, Weinheim, Prof. Cassian Schmidt gave me for my research and photographic work.

This special flower exhibits very prominent patterns under various filtering and lighting conditions which I would like to present here.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color normal + high intensity palette:

VIS:

UV using Baader-U2 (320-390nm):

UV using 333nm narrowband filter (325-340nm):

UV induced visible fluorence (I):

UV induced visible fluorence (II):

UV-VIS simulated bee vision:

VIS-NIR redge-edge:

So I hope you liked that too!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Zinnia shot at 333nm UV in the field

2011-07-19T20:38:00.003+02:00

Today about shooting Zinnias at 333nm in the field as I wanted to see, if it was doable.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color normal + high intensity palette:

VIS:

UV using Baader-U2 (320-390nm):

UV using 333nm narrowband filter (325-340nm):

and another one:

VIS:

UV using Baader-U2 (320-390nm):

UV using 333nm narrowband filter (325-340nm):

It seems to be doable on bright sunny days as it was today, but one has to certainly pray for less wind, since the exposure needed for the 333nm shot was substantially longer, 1-2sec @ISO1250.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Gazania - surprising UV patterns in reflected deep UV-A

2011-07-18T19:33:00.010+02:00

Today about another find, while I was shooting Gazania flower. I wanted to see here too if my "UV colors" would show up also in this case, as predicted by my false UV color palette according to the previously defined spectral UV-A sub-bands.

[click on images to see larger ones]

For the following shots, narrow band UV-A filters were used. And bear in mind, that very different exposure settings were used to produce these about evenly exposed images, as has been shown in a previous thread here.

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color normal palette:

UV (using Baader-U2, 320-390nm):

UV (using a 375nm filter):

UV (using a 333nm filter):

So in case you wonder how and why these colors emerge, have a look at the following graph which should explain it. Shown are various reflectance measurements of that yellow (in visible light) Gazania tip from outside towards the dark middle of that petal.

It gets clear that this yellow Gazania flower reflects quite deep into UV-A up to about 320nm. This also being the reason why that 333nm filtered image shows that bright green.

Here now the spectral measurement of the the one which appears purple outside in UV (orange in visible light), but has greenish tips and a little yellowish also on its inside petals which then rapidly disappears and gets quite dark. The scan started from the very top of the tip (turquoise line), then proceeds down the petal (we talk a few millimeters only), the greenish starts to give way to a more yellowish green (blue line) and then gets darker overall (green line) as it proceeds to the UV dark zone of the petal. The outside reflectivity of the petal shows the violet line.

Also here it gets clear that this orange Gazania flower reflects even deeper into UV-A up to about 312nm. This also here being the reason why that 333nm filtered shot shows that bright green. But overall the UV reflectivity was quite lower of this flower than that of its yellow flower sister.

So, also these experiments prove, that the "false UV colors" as seen in the above shown images, may be used to identify certain sub UV-A bands, as I have defined before: 300-320nm (turquiose), 325 - 340nm (green), 350 - 370nm (brownish yellow) and 375 - 400nm (violet) which are clearly separated, as may be seen here:

That used 375nm filter is just borderline between two sub-UV-A bands, so it shows a bit of both.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Phalaenopsis - surprising UV patterns in reflected deep UV-A

2011-07-15T16:25:00.010+02:00

Today about a special find, while I was shooting a well known flower, a Phalaenopisis orchid. I wanted to see if my "UV colors" would show also in that case as predicted by my false UV color palette according to the previously defined spectral UV-A sub-bands.

[click on images to see larger ones]

First the normal, visual light shot:

For the following shots, narrow band UV-A filters were used. And bear in mind, that very different exposure settings were used to produce these about evenly exposed images, as has been shown in a previous thread here.

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color normal palette:

UV (using Baader-U2, 320-390nm):

UV (using a 395nm filter):

UV (using a 375nm filter):

UV (using a 360nm filter):

UV (I) (using a 333nm filter):

UV (II) (using a very narrow 333nm filter):

Quite astonishing to see, how suddenly UV patterns start to emerge when the waveband is being shifted towards shorter wavelengths.

So in case you wonder how and why these colors emerge, have a look at the following graph which should explain it. Shown are both reflectance (orchid) and transmittance (filters), so be aware of that.

That white Phalaenopsis has some highly UV reflective parts, especially that prominent "nose" in its center (yellow line) that reaches quite deep into UV, until about 335nm. The Corolla (turquoise line) also does reflect UV, but only a bit and reaches down to about 380nm only.

The filters are Baader-U2 (violet line), 395nm filter (green line), 375nm filter (blue line), 333nm filter (pink line) unblocked, 333nm filter (red line) blocked.

Obviously that 333nm has a transmission side band in the 370-385nm region, which multiplied with the higher light intensity and sensor sensitivity leads to visible exposure (UV Image I). In UV image (II) this "leakage" got blocked.

The rest is self-explanatory, as it also explains the other images above and again confirms the validity of my "false UV color palette".

So, also this experiment proves, that these "UV colors" as seen in the above shown images, may be used to identify certain sub UV-A bands, as I have defined before: 300-320nm (turquiose), 325 - 340nm (green), 350 - 370nm (brownish yellow) and 375 - 400nm (violet) which are clearly separated, as may be seen here:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] GH1-UVIR false UV color palette proof using narrowband filters

2011-07-12T15:34:00.014+02:00

Well, today I took a few hours to conduct some photographic filter tests, as well as proving same using my spectrometer, to see if my "UV colors" would show as predicted by my false UV color palette according to spectral UV-A sub-band.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color normal palette:

Summed it all up in just one image here, which shows the transmittance of the filters used as well as copied small images of the photographic results using these filters. On the bottom for comparison my standardized false UV color palette:

Here the filtered images a bit larger (just cropped + resized, straight jpegs from the cam) [don't judge on photographic quality here, some filters are old and were found partially deteriorated]:

Filters used in sequence (stacked on Baader-U2 to block IR) were: 325nm Astro filter, Hoya U-350, Zeiss 375nm, Baader-K (unstacked, as it blocks IR itself).

Bear in mind, that very different exposure setting were used to produce these about evenly exposed images, as has been shown in a previous thread here! So, these false colors do not co-exist at the same time with the same intensity at the same wavelength stimulus (hence cannot be mixed), because of the very different sensor sensitivity to different UV wavelengths.

That shown Rudbeckia fulgida flower is very suitable for that, as its petal tip UV reflection covers about that whole 300-400nm range (320-400nm more precisely), as may be seen here:

Here how that whole scene looks like through the Baader-U2 filter, whitebalanced to that mentioned above false UV color palette:

So, also this experiment proves, that these "UV colors" as seen in the above shown images, may be used to identify certain sub UV-A bands, as I have defined before: 300-320nm (turquiose), 325 - 340nm (green), 350 - 370nm (brownish yellow) and 375 - 400nm (violet) which are clearly separated, as may be seen here:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] "dancing" Rudbeckia

2011-07-11T01:20:00.002+02:00

Just an "artsy" shot today, called "dancing"

[click on images to see larger ones]

and here the "scientific version of it:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] UV color of a flower leaf

2011-07-09T18:16:00.004+02:00

Today about why leaves do have some false UV color when shooting reflected UV. So a quick reflectrometric experiment sheds some light into that, here using a Rudbeckia hirta and a Rudbeckia fulgida leaf and comparing them with reflected UV shots.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color normal and high intensity palette:

The R. hirta leaf on the left shows some greenish/grayish reflection with some violet on it depending on angle. The spectrometeric result reveals, that indeed the highest UV reflection is in the violet sub UVA range, wheras there is also some in the yellowish/brownish sub UVA range, but only a little reflection in the greenish sub band.

The R. fulgida leaf on the right shows some greenish/yellowish reflection and not much angle dependency. The spectrometeric result reveals, that it has quite an even UV reflection, which reaches quite deep into the UVA range to about 310nm and has proportionally a higher green / yellow content than R. hirta.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] getting closer, using diopter lens

2011-07-09T01:23:00.005+02:00

Today about getting closer for reflected UV work. The old and simple method is to add a diopter (meniscus) lens. Will that work also here?

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color normal and high intensity palette:

It seems to work well obviously and the loss of UV transmission got compensated and the colors also acceptably represented (after proper whitebalancing).

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] standardized false color UV palette - a proof

2011-07-07T00:43:00.003+02:00

Today I made some experiments using UV LEDs to prove my standardized false color UV palette using reflected UV photography and my Lumix GH1-UVIR.

I had previously written about proper whitebalancing to reach a standardized false color UV palette and that sub UV-A bands exists that can be identified using one UV shot. Here is a simple proof that these false UV colors actually correspond to certain wavelengths (the proof has already been presented here using spectrometric measueremnts).

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

Standardized false UV color palette:

The reflected UV images show a Rudbeckia fulgida flower. Left using a Nichia 365nm UV LED; on the right using a 395nm UV LED:

Well, the match of the color in the image and the palette colors to the UV LED emitted wavebands are pretty obvious.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] whitebalancing using a 35mm wide angle lens for UV

2011-07-06T20:08:00.007+02:00

Today I made some experiments using wide(r) angle lenses for shooting reflected UV using my Lumix GH1-UVIR.

I had previously written about proper whitebalancing to reach a standardized false color UV palette using a true apochromatically corrected UV lens and also about doing that for other wide angle lenses. Now I wanted to reach about the same "colors" using such a lens which transmits much less UV, in that case here a 35mm c-mount lens.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

The normal and high intensity palette:

The reflected UV images show a Rudbeckia hirta flower. Left the result before applying my whitebalancing procedure; on teh right after whitebalancing using my ReflectionDisc (and some special in-camera tweaking):

[the colors on the left image are NOT according to the standardized palette!]

Well, as you can see, about the same colors could be reached on the right image, still a little different, as some parts of the spectrum are missing (the shorter wave UV-A sub-bands more specifically, so there is no green as that lens only transmits to about 350nm). Still it gets evident that this Rudbeckia flower has a UV reflection from its petal tips of around 360nm.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Zinnia - more on short wave UV reflection

2011-07-04T17:52:00.004+02:00

I was shooting Zinnias today, when I saw one which sported that greenish short wave UV-A sub band reflection as mentioned here before..

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

The normal and high intensity palette:

The reflected UV image shows that this Zinnia flower variant has a greenish / yellowish short wave UV-A reflection in the 340-360nm range:

VIS shot for comparison:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Zinnia flower competing

2011-07-04T15:07:00.005+02:00

I was shooting Zinnias today, when I saw one flowering aside another bright yellow flower. I noticed the Zinnias being frequently visited by bees and bumblebees, whereas the similar looking yellow one had only few guests.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

The normal and high intensity palette:

Well, the reflected UV image shows clearly how that Zinnia flowers wins the "competition":

Even covered by other plants it makes itself clearly seen (see blurry BG Zinnia). So not really "competition" for that UV-bright Zinnia (340-360nm).

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Rudbeckia hirta

2011-06-30T00:19:00.006+02:00

Today I found another nice Rudbeckia species (Rudbeckia hirta that is), which sports some interesting UV pattern.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

The normal intensity palette:

and this is the high intensity palette:

So here now the UV image of that flower:

So from that yellow UV color we may deduct that this flower UV reflection is from around 360nm.

And here the UV image of another flower and two young ones:

which shows quite different UV reflections (360nm region = yellow, but in the 385nm region = violet which the young ones exhibit)

For comparison here the VIS shot:

which shows quite different UV reflections (360nm region = yellow, but in the 385nm

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] spectrometric vs photographic results using standardized false UV color palette

2011-06-25T13:45:00.021+02:00

While I was shooting flowers at Herrmanshof, Weinheim park, I noticed some intense whiteish and some dimmer greenish UV reflectance patters (in my standardized false UV color palette) and I wanted to have some proof, if from the false color UV displayed it could be backward deducted about a specific sub-UV-A waveband reflection using spectrometric measurements .

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

The normal intensity palette:

and this is the high intensity palette:

Well, may I remind, that these false colors do not co-exist at the same time with the same intensity at the same wavelength stimulus (hence cannot be mixed), because of the very different sensor sensitivity to different UV wavelengths.

So from that above re-posted graph, which shows that GH1-UVIR sensor reaction to a monochromatic 5nm bandwith stimulus, for instance a 340nm "UV color" needs 4EV more exposure than one at 395nm and a 300nm needs even 6EV more.

This is why I found it so special to find a green response (340nm) and yellowish response (370nm) in the same image (Zinnias as shown; also the reason why the green is so dim and the whitish yellow so overexposed) as there is 3EV in between - and this is why I doubt to ever find sea-green (around 300nm) in such a photo (6EV difference) that would contain this violet (at 395nm) - except I use a special technique which already forms in my mind...

So if one wanted to simulate how the UV color would look like in a resulting photo, we could use the spectrometer output and would have to multiply it with the Baader-U filter transmittance actually and then look up the exposure values per intensity. Unfortunately the sensor also responds nonlinear over wide exposure ranges (so the above is valid for mid level exposures only), so that yields only a crude approximation. But at least one would get a clue why that petal tip appeared green - yellowish in that image as posted above.

Spectrometric result of such a petal of the following Zinnia variant, tip greenish, rest nearly black (in UV) and yellow tip, orange-red the petal rest in VIS:

Photographic result: VIS:left, UV:right

Following examples for comparison,: Bidens ferulifolia, petal tip looks bright yellowish and rest petal quite dark in UV and Sanvitalia procumbens which looks about the same UV color at its petal tip but dimmer and petal rest nearly pitch black in UV (using my standardized false UV color palette). Gaillardia aristata has an underlying UV reflective layer even over the whole tip under a in the visible yellow petal tip and orange-red rest of the tip; the flower center is all UV dark but in the visible orange red outside and greenish in the very center

Spectrometric results

Bidens ferulifolia:

Prediction "UV color": bright whiteish-yellowish tip, dark rest of petal; dark center

Sanvitalia procumbens:

Prediction "UV color": whiteish-yellowish tip, dark rest of petal; dark center

Photographic result: UV (right part of image is sunlight, left 365nm UV LED; Bidens left, Sanvitalia right):

Gaillardia aristata:

Prediction "UV color": bright whiteish-yellowish petal; dark center

Photographic result: VIS / UV (wet, after rain):

Added today:
Rudbeckia fulgida flower:

Prediction "UV color": yellow tip, dark rest of petal; whiteish-yellowish center reflection

Photographic VIS/UV:

So we see, that it holds true so far, that my standardized false UV colors can stand for specific UV-A sub-waveband reflections as shown here on my BLOG.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] white in standardized UV false color palette

2011-06-24T23:16:00.004+02:00

While I was shooting flowers at Herrmanshof, Weinheim park, I also noticed some intense whiteish UV reflectance patters and I wanted to explain that in my standardized false UV color palette.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

The normal intensity palette:

and this is the high intensity palette:

So if you have a look at the following image, you see that the left Zinnia flower shows such a high intensity response.

Now comparing that with the high intensity palette shows, that this only happens around 370-375nm. The proof of that is in the sensor response, which may be seen here, as there is only one very short waveband around 373nm, where all three R, G, B channels have about equal response (a condition to reach "white") - that yellow circle indicates that spot.

So also from that we may deduct that this flower UV reflection is indeed from around 373nm.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Zinnia variant shows 320-340nm UV reflectance

2011-06-23T14:54:00.010+02:00

Went back today to Herrmanshof, Weinheim park and found quite a few variants of that Zinnia flower, showing also very variable such visible and especially UV patterns. I also found that short wave UV-A bright one again.

Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter; standardized UV palette using my ReflectionDisc

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength:

I could get a flower sample and measured the reflection using a micro reflection probe, scanning the petal with it after having calibrated against (R) Spectralon.

Well and I'm happy to present the results here: that Zinna variant petal tip indeed reflects between 320-340nm (peak reflectance; four different positions shown), whereas the UV-dark part towards the center only shows some orange-red reflection (coincides with the visible).

That finding also confirms the ability of my false UV color standardization method to identify four sub UV-A bands per its individual color within a reflected UV-A shot. This allows to use such a camera also as a coarse spectrometric tool. The sub-bands have already been presented here:

Here a shot done in my lab of that flower (left: VIS, right: UV):

Here a macro shot done in my lab of that flower (left: VIS, right: UV):

And here a shot of such a flower in the park (left: VIS, right: UV):

I found some variants of that flower which more or less showed that same greenish UV reflection pattern:

That last example is interesting, as the UV pattern is very different in size and structure than the visible pattern.

But I think all these are man bread hybrids, so there is no real "biological meaning" (= selection through evolution) behind that short wave UV-A reflection in my opinion. Just interesting to see that there are indeed either pigments or oil droplets within the petals that allow such short wave UV-A reflection.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] mating frogs in UV

2011-06-22T20:20:00.003+02:00

While I was shooting flowers at Herrmanshof, Weinheim park, two frogs were sitting at the rim of a beautiful pond, very noticing my approac but patiently waiting till I was done with my shots - a very intimate moment between human and animal!

Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter; standardized UV palette using my ReflectionDisc

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength:

VIS:

UV:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] new vs old flower made visible with UV

2011-06-22T20:12:00.005+02:00

While I was shooting flowers at Herrmanshof, Weinheim park, I noticed that in UV the ageing of a flower can be easily detected, wheras in visible light, they look alike.

Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter; standardized UV palette using my ReflectionDisc

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength:

VIS:

UV:

These yellow Helianthus tuberosus flowers on teh left side, clearly show age differences: top is in male stage (early), bottom is in female stage (late) but in UV things get much clearer! So I'm sure our beesies knew that way before us...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] a first 340nm UV pattern?

2011-06-22T17:01:00.006+02:00

Today while I was shooting flowers at Herrmanshof, Weinheim park, for the first time I noticed some "green" UV reflectance pattern, that according to my standardized false UV palette looks like a 340nm reflection. Unfortunately it is unsharp, but I will try and re-shoot it later...

Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter; standardized UV palette using my ReflectionDisc

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength:

I wonder if I may get that flower and make some spectrometric reflection tests...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] Rudbeckia variants with nice UV patterns

2011-06-22T16:13:00.007+02:00

Today while I was shooting flowers at Herrmanshof, Weinheim park, I found some nice Rudbeckia spec) which I haven't seen before, sporting some interesting UV patterns.

Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter; standardized UV palette using my ReflectionDisc

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength:

and here one with hardly has any pattern:

I have much to show from that session later...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV] Rudbeckia inside out - different UV reflectances inside and outside

2011-06-21T13:49:00.007+02:00

Noticed today, how different the UV reflectance of a freshly unfolding flower (here Rudbeckia fulgida) could be, comparing the outside and inside of the flower petals. Totally invisible to the human naked eye, but surely not to pollinating insects!

Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter; standardized UV palette using my ReflectionDisc

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength:

UV shot:

VIS comparison shot:

I have some theory about that different reflection: I think it makes no (biological) sense that a flower attracts an insect when the flower is not ready yet, nor has anything rewarding to offer i.e. sending out (UV-) signals that would rather lead to "frustrated pollinators" which would most likely quickly learn not to visit such flowers anymore. So, having the outside, less UV-reflective "shield" the opening flower, makes it less attractive to insects, unless the flower has fully opened and also has nectar, thus rewarding pollinators for their visit.

Interesting to see how that UV pattern will develop within the next days; let's see ...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] influence of ray angle when using the Baader-U or classic UV filter

2011-06-20T20:44:00.010+02:00

Today again about the "workhorse" of reflected UV photography, the Baader-U "Venus" filter. The old Baader-U had 40 dichroitic layers, the new and currectly sold one has about 100 layers of dichroitic coatings, but on an ionic colored substrate (Schott UG11). That dichroitic coating is only applied to block the IR leakage that SCHOTT UG11 filter glass has, but not to define the filter characteristics itself, as in the case of a pure dichroitic filter on a transparent substrate.

It has been argued that dichroic filters are sensitive to the angle of incidence of the light and that the filter pass-band would be shifting towards shorter wavelengths. What was argued is, that if using wide angle lenses (which hardly exist for transmitted UV anyway), rays may enter the filter at such a high angle of incidence, that the filter transmittance and overall filter characteristics would severely be altered.

That mentioned effect is there of course, but in practice (at least in mine), I have never noticed a negative effect, also since my shortest focal length was about 28mm only and the largest sensor used APS format. At much wider angles and using a full format sensor it would certainly have more impact.

But let's just see how much impact in practice that really has...

Here a spectrometric measurement done in my optical lab (at 0-degrees and 45-degrees incident angle) to show the influence the angle of rays has.

[click on image to see a larger one]

So we see that about 10% in transmittance are lost at 45 degrees, which equals about -1/8 EV and so that has no real relevance on the photographic result. There is also some shift towards shorter wavelengths, but actually it is more a broadening of the total transmission band towards shorter wavelengths of some 13nm (325nm --> 312nm) on the left filter shoulder, whereas the right filter shoulder nearly remains the same (390nm --> 388nm) using the 10% transmittance values - that actually being a positive effect.

In summary the total transmitted energy (= proportional to the area under that curve) should stay about the same, so no effect on the exposure time should be expected, but an ever so slightest change in colors towards the edges of the image might be noticed, if using a full format sensor and a wide angle lens for reflected UV photography - which I have never noticed in my photographic practice.

Well and then there was a thought in the back of my head and I wondered what a ray at an incident angle of say 45 degrees would have to suffer if it had to pass through much more ionic classic "normal" i.e. uncoated colored filter glass at that angle in comparison to a ray at 0 degrees angle...

Here's the result, same setup as with the previously tested Baader-U filter, using the same basic filter glass: SCHOTT UG11

Interesting 12% peak transmittance loss, but no broadening of the transmitted band and no change in shape. In total also only about -1/8EV loss of transmittance, so not really of photographic relevance.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Rudbeckia flower unfolding, part II

2011-06-20T02:39:00.005+02:00

Today further shots of my first Rudbeckia flower this year I had written about before , using Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter

[click on images to see larger ones]

UV shot:

VIS comparison shot:

Interesting to see how that UV pattern emerges within days; let's see what's happening on the following days ...

[ssshh, did you see the guest?]

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Cerco 28mm multispectral lens

2011-06-17T14:34:00.003+02:00

Today about a CERCO 3.5/28mm multispectral lens, made of fluorite / quartz and a big CAVEAT upfront, as I'm using this lens way outside its defined range, which has been made to serve as a lens for an image intensifier system originally with a 18mm image diameter - I'm using 21.6mm, because that's the sensor diameter of my Lumix GH1-UVIR. So what has to be expected is a sharp and contrasty center, but most likely quite some fall-off outside that central area.

Mechanically this lens is very tiny, about half the size of my thumb, c-mount and has a rare front filter thread. Register is quite short due to its defined use for an image intensifier, but meets c-mount lens standards and even focuses from beyond infinity to about 0.5m (so it cannot be used on Nikon bodies, to make it clear).

[click on image to see a larger one]

Transmission is quite good and as expected:

[measurement valid from about 315 - 750nm]

That said, now to the UV and VIS test results. All shots done in sunlight, ISO640, f5.6, focus set in visible light, no focus adjustments done. ReflectionDisc in camera whitebalance, reduced to 1280pix, sharpened for web, contrast enhanced (UV).

1) Rudbeckia fulgida flower close-up (same camera position as in my shots shown in other thread here)

VIS:

UV:

2) Shot down to the city (infinity):

VIS:

UV:

3) Shot of our neighbors house (ca 30m):

VIS:

UV:

Especially from the last two shots it gets quite clear, that this lens was used outside its defined image circle and the loss of sharpness is evident. The close-up shots are much better (as could have been expected due to the much larger projected image circle). The image center is actually quite sharp and contrasty for such a lens and esp. when compared with a Noflexar 35mm, which it certainly beats in resolution and transmission (but the Noflexar 35mm has the benefit to cover a FF sensor). This lens was made for very faint light intensities, so no wonder that it shows some signs of flare if used at high light intensities (although proper shading was used), but I could not detect a prominent hotspot (which its brother, the Cerco 94mm has).

Overall a nicely performing lens for UV-VIS (I haven't tested it for IR) if used inside the specified range, but also quite an expensive one (UV-Nikkor range).

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS, BV] first Rudbeckia flower unfolding

2011-06-16T12:25:00.002+02:00

Today shots of my first Rudbeckia flower this year, using Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter

[click on images to see larger ones]

UV shot:

Bee Vision (simulated using filter):

VIS comparison shot:

The idea is to see, how the UV pattern emerges within the next days when the flower totally enfolds ...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Hungarian Parliament building in reflected ultraviolet light

2011-06-14T14:37:00.004+02:00

From a recent trip to Hungary, here a shot of the famous Hungarian Parliament building as seen from the Buda castle on the opposite side of the Danube river.

Shot using my Lumix GH1-UVIR, Cerco 94mm lens, Baader-U filter and preset UV WhiteBalance using my ReflectionDisc.

[click on image to see a larger one]

Reflected UV "colors" are according to the previously described "UV color palette" related to wavelength:

A visible comparison shot taken a few minutes from the one above looks like that:

Note the very different colors and especially the fogged background due to Rayleigh scattering of UV light which is much stronger for UV light than for visible or even IR light (this is why IR is so often used to penetrate clouds = make them transparent).

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Hungarian Puszta flowers in reflected ultraviolet light

2011-06-14T14:27:00.003+02:00

From a recent field trip to Hungary, a few flowers shots from the Kiskunsagi Nemzeti Park in the Hungarian Puszta.

Shot using my Lumix GH1-UVIR, Cerco 94mm lens, Baader-U filter and preset UV WhiteBalance using my ReflectionDisc.

[click on image to see a larger one]

A few butterfly shots in UV:

and the reminders of a predator:

Reflected UV "colors" are according to the previously described "UV color palette" related to wavelength:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] on wide angle lens whitebalance using a GH1-UVIR

2011-06-06T16:49:00.010+02:00

So, using my GH1-UVIR, a Cerco 94mm lens, Baader-U filter and sunlight, I had preset a whitebalance for a similarely lit situation using my Reflection Disc, call that WB1 for now.

The weather today was very overcast and no sun, just about 250 microWatt/cm² UV-A (as measured using a calibrated Minolta UV-A meter).

The lens was changed, from a color corrected, flat transmitting (<300nm) quartz / fluorite lens to a non-color corrected not that much UV transmitting conventional wide angle lens, a 2.8/28mm in that case, which barely reaches about 350nm, to see which impact that would have. A set WB was done for that 28mm wide angle lens, call that WB2.

So what we see here is:

1) top left: previously set sunlight WB used (WB1)

2) top right: correct WB for that lighting situation set (WB2)

3) bottom left: previously set sunlight WB used (WB1), bw version with histogram

4) bottom right: correct WB for that lighting situation set (WB2); bw version with histogram

[click on image to see a larger one]

Here now quite some difference in whitebalancing may be noted; the preset WB1 was quite different from the correct WB2 for that lens (and lighting situation). Major impact had the lens change, not the changed lighting. As may be seen on the histogram, the correctly whitebalanced image is about 1/4 - 1/3 stop less exposed than the incorrectly one (both images were identically exposed at 1/1.6sec, same ISO) , so consequently using the correct WB at shooting time would require a somewhat higher exposure.

SUMMARY: UV whitebalance, for lenses having very different spectral (UV-) transmission, should be correctly set at exposure, not later in post processing and properly exposed (a tad more).

P.S.: I have tested at different exposure values (higher + lower) but the principal result remained the same.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] on whitebalance tolerance using a GH1-UVIR

2011-06-05T18:00:00.008+02:00

In previous posts on whitebalancing using my ReflectionDisc I warned about generalizing results and stated that it is only valid for that camera, that lens, that filter and that lighting situation. Well, I was curious, how much would change if two parameters were changed: a) lens in use, b) lighting situation

So, using my GH1-UVIR, a Cerco 94mm lens, Baader-U filter and sunlight, I had preset a whitebalance for that situation using my Reflection Disc, call that WB1 for now.

The weather today was different, quite well lit, but overcast and no sun. A set WB was done, call that WB2.

Also the lens was changed, form a color corrected, flat transmitting (<300nm) quartz / fluorite lens to a non-color corrected suitably UV transmitting conventional enlarger lens, which reaches about 350nm, to see which impact that would have. So what we see here is:

1) top left: Cerco 94mm lens, correct WB for that lighting situation set (WB2)

2) top right: Cerco 94mm lens, previously set sunlight WB used (WB1)

3) bottom left: 95mm enlarger lens, correct WB for that lighting situation set (WB2)

4) bottom right: 95mm enlarger lens, previously set sunlight WB used (WB1)

[click on image to see a larger one]

Interesting to note, that only the blue and red channels are shifted just a bit, which can easily be corrected afterwards in post processing, but the image out of the camera is still quite close to the "correct" one.

That's important if you're out in the field and the lighting situation changes and / or different lenses are used (as long as they are suitably UV transmitting; this may not work for white angle lenses having hardly any UV transmission). For critical scientific work I would of course always do proper whitebalancing upfront.

SUMMARY: UV whitebalance, once correctly set, works suitably well also under changed situations (light, lens)

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] An attempt to standardize UV colors

2011-06-04T12:38:00.006+02:00

Some days ago I have shown, how a full spectrum converted camera may be whitebalanced in a way so as to reproduce distinct UV colors. I have also shown its relative spectral sensitivity.

Here now, in log2 scale (= exposure units) a graph showing these RGB color channels and how their response changes with wavelength.

This of course is valid only for this camera (Lumix GH1-UVIR ), the used lens (CERCO 94mm), used filter (Baader-U filter) and used lighting conditions (sunlight) strictly speaking; in pratice I noticed very similar results using UV LED light (Nichia 365nm), similar quartz fluorite lenses (UV-Nikkor 105mm etc.). The main influencing parts are of course the camera and the filter.

[click on image to see a larger one]

SUMMARY: The sub UV-A bands: 300-320nm, 325 - 340nm, 350 - 370nm and 375 - 400nm are clearly separated by different representing colors.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] GH1-UVIR vs D200-UVIR UV sensitivity test

2011-06-02T00:10:00.002+02:00

Today a comparison of the absolute UV sensitivity of a Lumix GH1-UVIR versus a Nikon D200-UVIR, both full spectrum converted [both conversions were done ensuring >90% UV transmission from 300nm onwards; without such conversion, both cameras have no useful UV response]. A detailed test of the UV sensitivity of that Lumix GH1-UVIR may be found HERE on my BLOG.

An identical target setup was used, a white and black ReflectionDisc with a set of SPECTRALON cubes having 100/50/25/12.5% reflectivity. A Xenon flash light source (mod. for high UV output), a Baader-U filter (320-390nm) and a CERCO 94mm quartz / fluorite lens were used for both cameras and the sensor size difference was compensated by proper adjustment of the camera positions, so that the resulting images showed approx. the same content. A series of shots were made with ISO 100 - 1000 in 1/3 stop increments. From these images, after proper whitebalancing (using my ReflectionDIsc), the Luminance values (range 0 - 255) of the 50% SPECTRALON reference cubes were read out and plotted, as those represent the midtones of the UV image.

[click on image to see a larger one]

At ISO125 the GH1 image was overall properly exposed, whereas the D200 needed ISO500 to reach the same exposure [from ISO800 the 50% gray of the GH1 went into saturation, hence the bent curve].

SUMMARY: The full spectrum converted Lumix GH1 has about 2EV higher sensitivity for UV, than the Nikon D200.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Sunlight vs Nichia 365nm UV LED - colors

2011-06-01T01:19:00.005+02:00

A quick experiment using the same preset WhiteBalance using my ReflectionDisc.

Lumix GH1-UVIR, Baader-U filter, ReflectionDisc for in-camera WB

[click on image to see a larger one]

Left: Nichia 365nm UV LED; Right: Sunlight:

Interesting to note, that the WB still holds and the proof for the wavelength "used" is in the middle (frosted glass on my balcony) - just compare the colors with the "UV color palette" I have pasted on top.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Reflected UV shots in the park today - decoding UV colors

2011-05-31T16:23:00.005+02:00

Just preparing and testing for a field trip, so some output here for your - hopefully - viewing pleasure...

GH1-UVIR, Baader-U filter, my ReflectionDisc for in-camera whitebalancind, leading to the following UV "color" palette:

[click on image to see a larger one]

The 375-390nm group (violet UV reflection):

The 350-370nm group (yellow UV reflection):

That last shot, a Helianthus tuberosus (in female state) image is quite interesting, as the full blooming flower shows a 350-370nm reflection, whereas the younger buds show some in the 375-390nm range. Obviously there are development stages in UV reflections, I would assume .

[excuse the little motion blur in some images, it was quite windy today...]

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Absolute UV Sensitivity of a full spectrum converted Lumix GH1-UVIR

2011-05-30T00:41:00.007+02:00

Today about the (coarse approximation of the) absolute UV sensitivity of a full spectrum converted Lumix GH1-UVIR after I had posted earlier about the Lumix GH1 sensor channel sensitivity.

This is based on a comparison of the exposure values used at that previous measurement series, as that was done ensuring equally exposed images using monochromatic UV light (an uncertainty factor of course, so keep that in mind).

Reference used was the exposure @395nm which was set arbitrarily as 0EV.

[click on image to see a larger one]

So this (astonishingly consistent linear!) result indicates, that an image shot at say 350nm would need about 3 EV more exposure to have an equally esposed image, than one taken at 395nm.

Or a working rule of thumb would be (for that camera!), that approx. any 15nm deeper into UV need one (1) stop more exposure. [monochromatic UV light, not to forget!]

It would be interesting to test this out with nearly monochromatic UV LED light, as there are 405nm, 395nm, 385nm and 365nm UV LEDs available.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

LUMIX GH1-UVIR relative channel sensitivity for UV

2011-05-25T02:53:00.004+02:00

Tried to read out a bit more info about the Lumix GH1 sensor channel sensitivity and used a RGB decomposition of the scaled color response I had made earlier. This is how the RGB decomposition then looks like.

[click on image to see a larger one]

Keeping in mind, that all images were scaled at shooting time to identical overall brightness, based on the given white balance (meaning that the channel responses were scaled) an only relative result may be deducted.

So read out, scaled and transferred to a graph, this leads to the following relative sensitivity graph:

Again, please remember that the images were recorded in a way so as to gain equally exposed images. So a 300nm shot took quite longer then a say 350nm or even 395nm shot!!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Lumix GH1 full spectrum spectra response; simple test

2011-05-25T00:16:00.004+02:00

To figure out the approximate spectral response of my full spectrum converted GH1, I played around a bit with some gratings and my stabilized, continuous Xenon light source. I also found a linear spectra of my Xenon lamp, so with its help an approximate calibration of the recorded spectra is possible.

The first line is the Xenon spectra, the second the unfiltered spectra as recorded by the GH1, the third line filtered through a Didymium calibration filter.

[click on image to see a larger one]

So from that and the color tests I published before, I would estimate that this full spectrum converted GH1 has a 320nm - 1000nm UV-VIS-NIR response. Actually I think it is more, as in such an image the exposure range limits the recording of fainter responses at the ends of the spectrum.

Found some better software which allows to read out such optical spectra. Here the results of using such:

On top the spectra as taken by photo, underneath the read out and calibrated spectra using known data high pressure Xenon spectra. The x-axis is in Angstroms, so knowing that 10A equals 1nm, it is easy to understand.

Again, please remember that the grating used was not really made for UV, but for VIS + NIR, so no wonder the spectra ends around 380nm. The real sensitivity to UV of that converted camera is quite higher, but I haven't found its limits yet.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

A few quartz flourite UV lenses on the bench

2011-05-25T00:00:00.002+02:00

As I was taking some measurements with the Coastal Optics UV-VIS-NIR Apo 60mm, I thought why not also testing a few other fully color-corrected lenses while I'm at it... (forgot the Coastal Optics 105mm, unfortunately...)

[click on image to see a larger one]

[validity: approx 310 - 750nm]

Interesting to note, how similar the older designs (Zeiss UV-Sonnar 105mm and LOMO UFAR-12 41mm) are, but the Pentax Ultra Achromatic Takumar 85mm beats them in terms of transmission. Then the UV-Nikkor 105mm and the newer CERCO 94mm; the newest being the most advanced development, the Coastal Optics UV-VIS-NIR Apo 60mm.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] the meaning of "UV colors", or how to read the color response of a converted UVIR cam

2011-05-24T16:30:00.011+02:00

If you ever wondered what the meaning of "UV colors" are, well, I may have an answers to that. Not in principle, but only for a specific camera and also for a specific WB calibration (on my ReflectionDisc in that case) and lighting situation.

The following refers specifically to a Lumix GH1-UVIR.

To do that, quite some work had to be done: using a monochromator and suitable UV light source, images were taken using that converted camera of the monochromator output in 5nm increments, specifically from 300nm - 700nm [UV - VIS], each whitebalanced using my ReflectionDisc to that light source. The center of that image was cut out and a map generated of those images (see color map at the end of this article).

Long story short, here the UV part of that map inserted into an UV image which had the identical WB.

[ignore the bad image quality, I just needed one with different UV "colors"]

So, as you see, that flower on the left reflects UV in the 380-390nm band, whereas the flower on the right does in the 350 - 370nm band.

It is interesting to notice, how the color changes around 325nm, 350nm, 375nm obviously based on changing responses of the three RGB sensor Channels.

Now, if you see a scene like that, you're able to "read" it, i.e. decode what these "UV colors" actually mean in terms of UV reflection bands. But bear in mind it has to be shot using the same camera, lens and filters and having applied the same whitebalancing and under similar light conditions (well, in reality it is not as bad as it sounds, there is some tolerance bands which I will talk about later here).

Of course more could be done using these images from that monochromator, for instance generating a sensitivity curve of the sensor... work for later maybe, so watch my BLOG.

A simple spectral response test can be found HERE.

Btw. the full UV-VIS color map covering 300nm - 695nm is here:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Bidens ferulifolia - visible, ultraviolet, bee vision

2011-05-23T02:37:00.001+02:00

One of my "usual suspects" - Bidens ferulifolia shot using the newly converted camera.

[click on image to see a larger one]

VIS (using UV/IR Cut filter):

UV (using Baader-U filter):

BV (using my prop. XBV3 filter):

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Reflected UV photography and video - handheld

2011-05-21T12:17:00.016+02:00

Well, today a long expected package arrived, just in time to make good use of the great weather we currently have here. But first a little about the Odyssee that Panasonic LUMIX GH1 camera took.

First about the camera "as is", as I had the chance to measure all optical relevant items, the internal cut filter (ICF) as well as the dust shaker glass (which has certainly more functions than just shake off sensor dust] - have a look at these images of that dust shaker, left taken in green light, right one in red light. Red light gets massively reflected. [thanks go to my new camera converter who was kind enough to document the process and provide photos]

And here the spectrometric measurements, dust shaker glass (pink line), ICF (teal line), overall optical transmission (violet line):

First conversion, done by a very professional and well reputed german company (name won't be mentioned). As I have the filters now to measure, here the results of their "full spectrum UVI conversion"

Although they highlight their ability to replace the shaker glass and have the dust shaker mechanism still working, what I got was the orginal shaker glass in place (bright pink line), that combined with their replacement UVI filter (pink line), which resulted in the overall transmission of the UVI converted camera (green line) I got. No wonder I got these extremely long exposure times (>15sec) for UV and also IR, since the dust shaker filter cuts sharply all below 420nm and above 650nm. I sent the camera back, as it could not be used at all for the intended purpose, but got it back in same state, "all in order".

Then I found another professional where I discussed these issue and immediately knew I would be in good hands, as we also agreed to very carefully analyze what had been done wrong and how to now make it work. Both UVI filter and shaker glass were carefully removed and replaced after some discussion with best available silica glass of suitable thickness (rose line) for the internal filter and the dust shaker glass. Alternatively some borofloat glass could have been used (teal line), but I went for the better. For comparison the previously inserted UVI filter is also shown (violet line). [My spectrometer is not even good enough to measure that silica glass, as it transmits flat >80% beyond 300nm towards 200nm].

Now the overall transmission looks like that:

So now my camera is just limited by its life NMOS sensor response, whose limits still needs to be tested out (so keep tuned in here...).

Eager to know what the photographic results would be, I took a few test shots under various conditions (sun, half sun, shade) and compared the results.

As it is a full spectrum converted camera, it needs a filter to shoot correctly balanced VIS shots. I use a Baader UV/IR Cut filter and Schott BG38 for that (both about replicate the filters it had in before, except that more suppressed red; it needs some adjusted WB because of that, but that only matters for in camera jpgs, RAW files are not affected by WB issues anyway). For UV I use the excellent Baader-U filter. Difference in exposure VIS to UV was 6.5-7 EV (D200 UVIR needs 8-10EV for comparison); the camera as is, without any external filters, has an even 3.5EV higher sensitivity as VIS.

In camera whitebalance was done using my ReflectionDisc which worked perfectly and immediately delivered well balanced UV shots.

But the best is its ability to use high ISO values (I used up to ISO1600 for handheld shots) and a perfectly clear working, bright lifeview, also with Baader-U filter attached to the taking lens - which waves goodbye focusing problems caused by most lenses having color shift.

A few handheld examples, in camera jpgs, unmodified and uncropped 14Mp images, just resized, shot using ISO1600, custom WB (using my PFTE ReflectivityDisc), CERCO 94mm quartz/fluorite lens, Baader-U filter and 1/5-1/40sec exposure times (good that I have a steady hand) [click on image to see a larger one]

Using a tripod certainly helps a lot, one example here (VIS, UV):

These stills taken in shadow using a tripod were exposed as:
for the UV shot: Exposure time: 1/2.50, F-stop: 5.6, ISO speed: 640
for the VIS shot: Exposure time: 1/800, F-stop: 5.6, ISO speed: 640

Here a street shot (1/10sec, f5.6, ISO640)

And HDTV UV video is also possible:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS, NIR] WhiteBalancing options

2011-05-21T03:14:00.002+02:00

Well, I had presented my Reflection Disc solution, which had been tested against (R) Spectralon when a forum member came up with the remark, that there are commercially available gray cards available, claiming to also work equally well in UV. So of course I got one and run tests against the industry standard (R) Spectralon as well as against my Reflection Disc (approx 75% reflection). That WhiBal Card has a white, a black area also, as well as a large gray area - all have been measured.

Long story short, here are the results.

[click on image to see a larger one]

SPECTRALON (100=rose, 50=violet, 25=teal, 12.5%=green); ReflectionDisc=blue, Whibal Card (white = yellow, gray=pink, black=red)

[confidence area: approx. 360 - 775nm]

SUMMARY:

That WhiBal card is certainly useful for VIS + NIR, but not for UV.

The PTFE ReflectionDisc certainly is not perfect, but works quite well in practice and delivers jpgs directly out of the camera with acceptable whitebalance for UV, VIS and NIR, also for a quick exposure check.

Here the photographic proof of the above - reflected UV using Baader-U filter and Xenon flash.

The card should be "white" or light gray, which it isn't. The cubes are Spectralon laying on my ReflectivityDisc.

It does work well in NIR though - here the card appears gray as it should be.

The cubes are Spectralon and my ReflectivityDisc stay the same color.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

UV Rain storm approaching

2011-05-19T15:35:00.000+02:00

A rain storm was approaching today while I was shooting flowers; makes an interesting UV image!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Double Diptych : Bidens - Sanvitalia VIS vs Bee Vision

2011-05-19T15:32:00.000+02:00

A diptych today, comprising a Bidens ferulifolia and Sanvitalia procumbens flower side-a-side in normal VIS and a bee vision (as seen through my one-shot propriatory XBV3 filter).

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Some of my UV Bee vision work on exhibit....

2011-05-13T19:37:00.004+02:00

So if you like to see some of my UV Bee Vision work

...and you live in the US, then you have a chance to see some here (East to West):

New York Botanical Gardens, NY (exhibit about bee vision)

Longwood Gardens, Kennett Square PA (exhibit about bee vision)

Natural History Museum, Bolder CO (exhibit about bee vision)

Humboldt Coastal Nature Center, Arcata CA (exhibit about bee vision and pollination)

...and you live in the EU, then you have a chance to see it here:

Natural History Museum, London (exhibit about butterfly vision as part of "sensational butterflies" exhibit)

All exhibits are different and were designed by the local authorities, whereas I provided assistance and advice as well as my photos.

I'm always happy to help raise the awareness about how beautiful yet fragile our nature is, so I guess that contributes a bit, especially as it also teaches the next generations to come.

Some impressions from the permanent installation at The New York Botanical Gardens

Images (c) The New York Botanical Gardens

[UV-VIS-NIR] ReflectionDisc for Whitebalance

2011-05-06T13:37:00.016+02:00

Well, I had presented a white ReflectionDisc I had made a while ago and Bjørn Rørslett has conducted an elaborate test about it on Nikongear Forum. This covered the "white point" for reflected UV photography - but the other end was missing before. Bjørn had overcome that with a clever idea by using an IR filter as a "black point" reference (works only for reflected UV, but not for IR of course). But I wanted some "universal solution" for UV-VIS-IR. So after some search I just found some adequate material with about 10% reflectivity (compared to the white disc) covering the UV-VIS-NIR range at least from 300-850nm (what my spectrometer covers). Just to repeat, this is what I had presented:

[click on image to see a larger one]

VIS:

UV (shot through Baader 2" U-Filter)

[the squares are SPECTRALON pieces with well definied reflectivity: Spectralon ® 100, 50, 25, 12.5%]

Spectral graph:

The blue line is the "white disc" with about 75% reflectivity, whereas the other lines show the reflectivity of the SPECTRALON cubes with 100, 50, 25, 12.5% reflectivity.

Here now a quick comparison covering VIS and reflected UV photography (UV for short in the course here). The white is the "white disc" as above, the dark material what I will use to make the "Black Disc".

This has been shot using a modified for high UV output Xenon flash, a non focus shift CERCO 94mm UV-VIS-NIR lens and a Baader U-filter for UV, resp. Baader UV/IR Cut filter for VIS.

Top is straight out of the camera with some approximate setting to even out the direct jpg result, bottom is after "click white" in Bibble Pro V4.9. Left is VIS, right is UV:

As may be seen, the histograms do not perfectly match (yet), even after some "click white" adjustments, but for direct fast jpg results, it should nicely do a starting point for further adjustments. I leave that to the well "known suspects" here... ;)

Here the same setup with an additional B+W 092 IR filter as "UV black" reference:

SUMMARY: So what we have now is the "white point": white reflectivity disc, the "black point": IR filter and a "grey/black point": black reflection disc

Here now in practical use, shooting a Bidens ferulifolia flower

Top row: uncorrected; Bottom row: after WB using reflection discs:

P.S.: no further (needed IMHO) adjustments done except WB!!

P.P.S.: I have now also a black ReflectionDisc with uniform and well defined UV-VIS-NIR reflection:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, BV, UV] Sanvitalia procumbens: visible, ultraviolet, bee vision

2011-04-21T15:14:00.003+02:00

Sanvitalia procumbens shots using the CERCO 94mm lens, mod. Xenon flash, ISO200/400, 1/125s, f5.6. The needed adjustments were done by adjusting the flash energy and using a ND filter for the VIS shot.

Baader UV/IR CUT filter (VIS):

XBV3-filter (BV bee vision):

Baader U - filter (UV):

Interesting to note, that the lower flower has much less of an UV pattern maybe denoting a different ripening status?

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[VIS, UV, BV] Bidens ferulifolia : visible, ultraviolet, bee vision

2011-04-20T19:33:00.002+02:00

Bidens ferulifolia shot using the CERCO 94mm lens, mod. Xenon flash, ISO400, 1/80s, f5.6. The needed adjustments were done by adjusting the flash energy and using a ND filter for VIS.

[click on image to see a larger one]

Baader UV/IR CUT filter (VIS):

XBV3-filter (BV bee vision):

Baader U - filter (UV):

I found this ensemble rather interesting, as I could get an "unripe" flower bud also into the picture (top right) - without signs of an UV pattern.

Now one day later I took another series of shots (a bit differently processed though), here they are:

Baader UV/IR CUT filter (VIS):

XBV3-filter (BV bee vision):

Baader U - filter (UV):

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Lumix GH1-UVIR full spectrum converted

2011-04-11T19:56:00.003+02:00

Well, after having shown that a unconverted Lumix GH2 does not really work for UV, here now testing the UV capabilities of a full spectrum converted Lumix GH1 camera. Lens used was the CERCO 94mm and filters were Baader-U filter for UV, Schott BG38 for VIS .

[click on image to see a larger one]

left: VIS image, right UV image. 1st picture "as is", 2nd UV image adjusted to taste.

Taraxacum

Fritillaria

So, still some research needs to be done, as I'm not fully convinced yet and need to experiment more with it, also check the RAW files as these pictures above used in-camera jpg conversion.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] Lumix GH2, unfortunately not...

2011-03-26T11:26:00.002+01:00

Well, I though I should also maybe report on "what doesn't work" from time to time. Here testing the UV capabilities of an off-the-shelf Lumix GH2 camera. I had to push ISO virtually to its limits, to see at least a bit of UV response. Lens used was the CERCO 94mm.

[click on image to see a larger one]

VIS:

UV:

VIS:

UV:

VIS:

UV:

So for sure without internal filter replacement, no chance to be useful! And even with a clear filter glass inside, I have not yet heard about its usefulness. But quite impressive is the ability to use ISO10.000 with still somewhat useful results. That 18Mp CMOS sensor is quite neat, especially for normal, visual light images and even better than the one of my older GH1.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Cerco lens does Perigee Moon UV-VIS-IR

2011-03-21T02:05:00.005+01:00

Well on March 19th, the moon was at its Perigee, closest to earth until 2029 and very bright, so I took a few shots using that CERCO 94mm lens here on my BLOG .

[click on image to see a larger one]

UV image:

VIS image:

IR image:

And after some multispectral processing using the images of above, one gets that "false color" image:

NASA and other agencies are using these types of false color images to display results of their satellite imaging.

Some better processing even gives it a more 3D appearance:

Here now a simulation, how an UV-Moon would look like as seen from Earth (Weinheim Castle "Windeck"):

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

CERCO f4.1/94mm VIS lens test

2011-03-11T15:23:00.010+01:00

Well, I recently bought that lens made by SODERN in France (type 2085) and had reported about it here on my BLOG . It is no longer available on stock (but on special order from 10 onwards) and has been superseded by the faster 2.8/100mm type 2178. Manufacturer site is linked here.

Now a few images of some early flowers taken a few days ago on a cold, but very sunny spring day.

[click on image to see a larger one]

Images are straight from the camera (Lumix GH1), uncropped. I have used a very deep sunshade and also only stopped down to about f5.6 because of that previously mentioned hotspot when stopping down too much. So under controlled lighting conditions, that lens is a decent performer and shows no hotspot issues for closeup work and also for infinity. Quite nice I have to say.

More testing has to be done of course...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV, VIS] Spring Daffodils meet ZEISS UV-Sonnar 105mm

2011-03-05T21:53:00.000+01:00

Today some experiments using a ZEISS UV-Sonnar 105mm, Hasselblad 501 C/M body and Phase One digiback. Target were some spring daffodils which had just started to flower.

[click on image to see a larger one]

So here side-a-side the VIS and UV shot:

[that "black" background cardboard I was using was not black in UV]

Not much to see in UV except the lit tips on the petals and the structure on that petal surface which gets visible.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Flourescent Lilly using UV LED torch

2011-02-24T01:49:00.001+01:00

Here a result of some fluorescence study using that wonderful Lilly flower I had used before.

Light source was a UV LED torch.

[click on image to see a larger one]

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[IR ev. UV] Makario found a way to use the D7000 at high ISO

2011-02-22T15:29:00.003+01:00

I had reported ealier about that problem that IR and UV images will be spoiled through that built in shutter control unit for modern Nikon DSLRs (D3, D3x, D3s, D700, D7000) here on my BLOG.

Now there is good news on the D7000!

I got the info today that Optic MAKARIO in Germany found a way to modify a Nikon D7000 in such a way, that the spoiling of the image through that built in shutter control IR LED system at high ISO / long exposure times will be suppressed. ISO 800 and 1600 are now possible to use with very good results. The effect still exists but in much lower amounts, so at very long exposure times and very high ISO settings it will still be visible though.

This was tested out good, I was told, for shooting IR and my personal assumption would be, that this can be applied for UV work, too.

Stay tuned, more will follow on that fascinating subject...

P.S.: (as of July 2011) lifepixel.com now offers conversions for D7000 in the US which also overcomes that problem and allows high ISO and long exposure times without fogged images!

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos