Tuesday, May 19, 2020

Treasury flower - Gazania rigens in reflected ultraviolet photography and simulated bee and butterfly vision XXXII

Today in 2020 more outdoor shots of that long blooming yellow Gazania flower, the Treasury flower - Gazania rigens shot in reflected ultraviolet photography, simulated bee and butterfly vision. All shots were done at f8 in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, as well as my XBV filters for simulated bee and butterfly vision. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated butterfly vision:
 

Simulated bee vision (alt. version):
 

Quadriptych of human vision, UV, simulated bee and butterfly vision (left to right, top to bottom):
 

This Gazania's outer petals strongly reflect UV around 365nm, whereas the inner petal parts are quite darker, hence forming UV nectar guides for UV seeing insects. There are also some highly UV reflecting marks inside around a dark UV center, all invisible to us humans, but clearly visible to bees and butterflies, and all this gets nicely visible here, also in simulated bee and butterfly vision.

I have written about this Gazania previously 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

Treasury flower - Gazania rigens in reflected ultraviolet photography and simulated bee and butterfly vision XXXI

Today in 2020 more outdoor shots of that long blooming yellow Gazania flower, the Treasury flower - Gazania rigens shot in reflected ultraviolet photography, simulated bee and butterfly vision. All shots were done at f8 in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, as well as my XBV filters for simulated bee and butterfly vision. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight, background was frosted glass.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated butterfly vision:
 

Simulated bee vision:
 

Quadriptych of human vision, UV, simulated bee and butterfly vision (left to right, top to bottom):
 

This Gazania's outer petals strongly reflect UV around 365nm, whereas the inner petal parts are quite darker, hence forming UV nectar guides for UV seeing insects. There are also some highly UV reflecting marks inside around a dark UV center, all invisible to us humans, but clearly visible to bees and butterflies, and all this gets nicely visible here, also in simulated bee and butterfly vision.

I have written about this Gazania previously 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

Monday, May 18, 2020

Treasury flower - Gazania rigens in reflected ultraviolet photography and simulated bee and butterfly vision XXX

Today in 2020 more first outdoor shots of a long blooming flower, a yellow Gazania flower, the Treasury flower - Gazania rigens shot in reflected ultraviolet photography, simulated bee and butterfly vision. All shots were done at f8 in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, as well as my XBV filters for simulated bee and butterfly vision. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated bee vision:
 

Simulated butterfly vision:
 

Quadriptych of human vision, UV, simulated bee and butterfly vision (left to right, top to bottom):
 

This Gazania's outer petals strongly reflect UV around 365nm, whereas the inner petal parts are quite darker, hence forming UV nectar guides for UV seeing insects. There are also some highly UV reflecting marks inside around a dark UV center, all invisible to us humans, but clearly visible to bees and butterflies, and all this gets nicely visible here, also in simulated bee and butterfly vision.

I have written about this Gazania previously 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

Sunday, May 17, 2020

Apache beggarticks - Bidens ferulifolia in deeper reflected ultraviolet photography, simulated bee and butterfly vision XVI

Today in 2020 more shots of that long blooming spring flower Apache beggarticks - Bidens ferulifolia in reflected ultraviolet photography. All shots were done at f8 in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, as well as my deeper UV filters and the IDAS 330nm filter. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was my UV enhanced Xenon flash.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Reflected deep UV with IDAS fiter (300-380nm, peak 330nm):
 

Reflected deeper UV (290-340nm, peak approx. 320nm):
 

Quadriptych (details) of human vision, UV, deep and deeper UV (left to right, top to bottom):
 

Bidens has a strong visible UV pattern, its petal tips are UV bright around 365nm, its center is quite UV dark, so this gets quite nicely visible, also in deep and deeper reflected UV photography.

I have written about Bidens previously 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

Apache beggarticks - Bidens ferulifolia in reflected ultraviolet photography, simulated bee and butterfly vision XV

Today in 2020 first shots of a long blooming spring flower Apache beggarticks - Bidens ferulifolia in reflected ultraviolet photography and simulated bee and butterfly vision. All shots were done at f8 in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, as well as my XBV filters for simulated bee and butterfly vision. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was my UV enhanced Xenon flash.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated butterfly vision:
 

Simulated bee vision (alt. version):
 

Quadriptych of human vision, UV, simulated bee and butterfly vision (left to right, top to bottom):
 

Quadriptych (details) of human vision, UV, simulated bee and butterfly vision (left to right, top to bottom):
 

Bidens has a strong visible UV pattern, its petal tips are UV bright around 365nm, its center is quite UV dark, so this gets quite nicely visible, also in simulated butterfly and bee vision.

I have written about Bidens previously 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

Thursday, May 14, 2020

Surprising STEINHEIL f2.8/50mm lens for reflected UV photography VII - Focus Shift

This again is about this older 50mm lens, which was made decades ago by famous lens maker STEINHEIL which attracted me, since it showed some seemingly good UV transmission, which have already shown here. I have already shown that it performs quite well using the Baader-U filter, and using some even deeper reaching UV filters, using a 340nm shortpass and the IDAS 330nm filter (I have the 2" version, no longer made).

Now I wanted to show today how the focus shift of this, or any other lens can be easily made visible. All images shot at f8, using a modified Xenon flash.

[click on image gets you a larger image]

VIS image using UV/IR Cut filter:
 

UV image using Bader-U filter (approx. 320-390nm, peak 360nm):
 

UV image using IDAS UV filter (approx. 300-380nm, peak 330nm):
 

UV image using 340nm UV filter (approx. 320-340nm):
 

Now it is about to show how those images differ in size, using a method I call "differential", i.e. a subtraction of two images, one visible and one UV, where any focus shift will show as overlapping on the borders of the object. If you looks close you will see this around the object.

VIS-UV (Baader-U filter) differential image:
 

VIS-UV (IDAS UV filter) differential image:
 

VIS-UV (340nm UV filter) differential image:
 

It got quite obvious before, that this lens is also performing very well at even shorter wavelengths, making it a very useful lens for reflected UV down to 330-340nm at an optimal f8/f11 setting, especially since the image size deviation between visible and UV image is also only 1.3% , which can be easily seen (and measured) from those differential images.

I have written about that lens more 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

Tuesday, May 12, 2020

About White Balancing and Spectralon (R) Standards

Quite a while ago I had written about white balancing reflected UV images. This meant to use a standardized white or grey standard to balance images, here "white" means that its reflection in visible light, but also in UV and ideally NIR is about the same. A very well know material for that is SPECTRALON (R) made by company Labsphere. It is "the" industry standard in laboratories and is used for spectrometry very often. It is made of specially prepared and cleansed Tetrafluorethylen  (PFTE) or TEFLON (R) powder. It is a rather pricey material. I had previously presented possibilities of cheaper acceptable options for photographic use HERE for instance using virgin white Teflon.

So today it is about what can happen to Spectralon standards, and which influence this may have.

I have used a Spectralon multi-step target, which consists of four zebra-striped panels of 99, 50, 25 and 12% reflectance which are mounted side-by-side.

[click on image to see a larger one]

Measured reflection of Labsphere SPECTRALON multi-step target (the white one was used as a 100% reference):
 
It gets obvious, that this multi-step standard still works very well and that the 99, 50, 25 and 12% reflectance values are still working.


Now in comparison a white Spectralon 99% target I bought, which may have been used for quite a while. As it did not look that great, I had sanded it down and cleaned it (light blue line approaching the 100% line):
(double lines are repeated measurements using a different distance)


But it gets rather obvious now, that this used standard must have aged quite a bit or some substance had penetrated its once white surface, as it still looks a bit yellowish and the reflectance measuerement clearly shows that, especially in UV.

I may have to repeat the sanding down process, but this time I will have to take away much more from its surface, using clean sanding paper, ending with 240 and 480 grit, to keep it matted.

Never touch that surface with bare fingers, only rinse with clean alcohol and or purified water and let it dry, don't use pressured air as it often contains oil droplets.

Labsphere has some information on their products as well as about proper handling HERE.

I have written about white balancing before 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