Wednesday, April 22, 2009

Bidens ferulifolia - Bee Vision II

I have worked a bit more on that XBV filter and have an XBV2 filter now also, which gives a more neutral representation.

[click on image to see a larger one]

For comparison the "bee vision" filter XBV as before:


an the more neutral XBV2 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

Phalaenopis - UV, FL, Nichia 365nm UV LED

Just some test shots using a Phalaenospis ("moth orchid") as a target.

Nikon D70 (unmod.), High Power UV flash, EL Nikkor 105mm, f8, 1/180sec, ISO400

[click on image to see a larger one]

VIS:


UV using Baader U filter:


FL using XCUT2 filter:


FL using Nichia 365nm UV LED (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

Bidens - 365nm vs. 385nm: Is longer better?

Well, I could not resist that one....BIGGRIN

But seriously, since I have two Nichia LED heads, one with 365nm (NCSU033A, 250mW) and also one with 385nm (NCSU034A, 330mW), I wanted to see, if in an identical controlled setup there would be significant differences in favour of using the shorter or longer wavelength.

Target was again Bidens ferulifolia, camera a Nikon D70 (unmodified), Baader U-filter (310-390nm), 100mm old enlarger lens (good to 320nm) and the only change done was the change of the UV LED used; Identical exposure.

[click on image to see a larger one]

365nm straight from the cam, no WB:



385nm straight from the cam, no WB:


365nm straight from the cam, WB:


385nm straight from the cam, WB:


Not much differences I would say, the pattern gets nicely visible and also some structures of the petals are shown in both shots (with that flower! Others may react quite differently, so be aware...).

But, yes there is a BUT: 365nm is much more complicated to reach if you don't have a suitable UV lens. 385nm however may be reached with about any lens (with some focus shift most likely), so if you are on a tight budget, or just just want to explore if UV photography would be for you, 385nm might serve you well and save you some serious amount and still some acceptable results may be reached (depending on target, let me say that again...)


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

Tuesday, April 21, 2009

Bidens ferulifolia - Simulated Bee Vision

Well, and how might a bee now see that flower? Let me show you my "bee vision version" of that flower, compressing the UV information into the human spectral range, i.e. I use the visible and the UV image (cf. my previous BLOG entry on Bidens) and overlay them in a certain way, so as to get the UV-B-G information in one image. As you may see, this is quite a cumbersome process, since ideally one would need two identical shots, one UV and one VIS, to get an exactly matching result, which due to wind, mechanical movement when changing filters etc. is pretty impossible:

[click on image to see a larger one]



Now I was curious to see, if I could have that very same result with just one shot using a suitable filter, and indeed this seems to be possible! I call that filter now my "bee vision" filter XBV:


It is pretty obvious that the "one shot" bee vision image reveals plenty more information, if you look at the petals, the pollen on the anthers etc. No wonder actually, since the overlaying process destroys fine details since a perfect overlay of two shots minutes apart can never perfectly match! And forget that when there is the slightest brise of wind...

For the more scientifically interested (esp. why these tips are so bright, which cannot be seen in visible light with our human eyes), here a reflection measurement I just made (100% = white spectralon) which clearly shows the high reflection of the petal tips in the 300-400nm region, max. around 360nm - the maximum of the bee UV cone sensitivity. Coincidence? I don't think so....:

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

Monday, April 20, 2009

Bidens ferulifolia, various filters + light sources

Well, another nice target for UV photographic experiments is Bidens ferulifolia, the variety "Peters's Surprise".

Equipment used was: Nikon D70 (unmodified), ISO400, f5.6-8, 1/160sec, old 100mm enlarger lens.

[click on image to see a larger one]

VIS using XCUT2 filter (400-650nm):


UV using Baader U-filter (310-390nm) - synthetic DOF:


XUVIR multispectral filter (300-1000nm), UV Flash:


UV induced fluorescence using XCUT2 filter (400-650nm), UV flash:

So, as you may see, a variety of results also that flower shows us.

P.S.: if you wonder what "synthetic DOF" means, I used "stacking" to increase the DOF artificially.


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

Thursday, April 16, 2009

Creeping Zinna, multispectral, UV induced fluorescence, reflected UV etc.

A walk over the local market not only brought some nice white "Lambertheimer" asperagus and new "Galatiner" potatoes home, nope, also a nice "Creeping Zinna" (Sanvitalia procumbens) plant made it to my balcony.

An ideal target to test out the UV enhanced High Power Xenon, the XUVIR "one shot" filter, the Xcut2 filter as well as the well known Baader U filter.

Equipment used was: Nikon D70 (unmodified), UV Nikkor 105mm lens @ ISO400, f11, 1/180sec.

[click on image to see a larger one]

VIS using XCUT2 filter (400-650nm):


UV using Baader U-filter (310-390nm):


XUVIR multispectral filter (300-1000nm), UV Flash:


XUVIR filter (300-1000nm), unfiltered flash for multispectral recording


UV induced fluorescence using XCUT2 filter (400-650nm), UV flash:


Sanvitalias UV pattern is actually not that easy to shoot. That may been seen if you have a look at the reflection spectra which I took, since the UV reflection of the petal tip (white line) is less than 10%, just a little bit more than the rest of the petal (teal line) which has hardly any UV reflection. At the same time the IR reflection is very high. So very careful filtering and a strong UV source is needed :


So, as you may see, a variety of results may be produced....and yes, the asparagus was delicious...

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

Wednesday, April 15, 2009

Cheap UV flashlight for reflected UV photography?

Cheap UV LED Flashlights from China flood the market now, so the question was, if tehse would be suitable to do reflected UV photgraphy. Therealöly cheap ones have 390/395nm UV LEDs built in - these won't work anyway since the used Baader U-filter cuts off at 390/395nm. But there are others, namely the 380/385nm versions and the more expensive 370nm versions which seem to be suitable.

A quick test now comparing the results with that of my UV enhanced High Power Xenon flash when doing reflected UV photography.

Equipment used was:  Nikon D70 (unmodified), Baader U-filter, X35 lens. Exposure: f8 and 2sec for the UV flashlight, 1/160sec for the UV flash at ISO400.

[click on image to get a larger one]

UV LED - That LED is NOT the Nichia UV LED I usually use, so don't get confused:



UV Xenon High Power Flash:



I guess the UV flash investment is well worth it, since it reveals much more fine details, stimulates all RGB channels of the camera chip and seems to also go much deeper into UV (a prior result showed response down to 320nm). But I have to be fair, for a simple setup or a beginner on a tight budget  it might well be worth trying and move on 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

Friday, April 10, 2009

Happy Multispectral Easter!

Easter is here again and I would like to take the opportunity to thank you all for reading my BLOG and be with me on my journey to these unknown lands of UV photography. I am surprised that after some years there are still areas which are completely new to me and I like that a lot! So that might be the reason for my "standard" closing sentence:
"Stay tuned, more will follow on these fascinating subjects..."

So again, Happy Easter to you and your family!

[as usual, a click on the image opens up a larger view]


UV + IR remapped into one visible image....


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

Sunday, April 5, 2009

Where to go....XUVIR full spectrum filter

A very short contribution here, a test using my new XUVIR full spectrum filter, using a Nikon D70s (mod. with clear quartz glass window >270nm) and a soft focus lens f2.5 85mm. [click on image to see a larger one]


[UV: blue, VIS:green, IR:red]

I won't comment on that for now....


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

Friday, April 3, 2009

You like Flyfishing? UV helps you be more successful!

You like flyfishing?

Well, UV photography can help you be successful doing that!

If you ask why, the simple reason is, that the scientific work on fish vision tells us that fish (some) have four receptors in their eyes, one each for blue, green and red (as we humans have) plus they have a forth, UV sensitive one!

I have been contacted by someone who wanted to find out, why some artifical flies work so very well, when some others don't at all. He sent me a package of very different ones, to test them out using reflected UV photography.

Lens used was my calibrated for UV X35 lens plus for the UV shot the Baader 2" U-filter. Light source used was my high power UV flash system.

So 'nuff talked, lets see some results! [click on image to see larger images]

Here now the comparison shot, the visual shot and the UV shot. VIS first then UV (color versions - UV has no color, so ignore that please!!) 




and here the black and white version of above for easier comparison of the different reflection patterns these flies have. VIS first, then UV:




It gets quite obvious, that a bright fly in visual light does not necessarily have a high UV reflection. Compare for instance the two leftmost flies in the top row. That artificial prawn left is highly reflective in visible and UV light, but the same light fish like fly one to the right is not at all in UV! But if you look at the bottom row, that dark two-colored fly (2nd from the right) is very bright in 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