• Ultraviolet Photography

A striking flower in UVB

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#1 dabateman

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Posted 16 July 2019 - 07:26

I typically don't see a huge difference in the UVB when imaging flowers. However, this one was different and I like the UVB image.

All shots are taken using Pentax UAT lens at F8, with a full spectrum modified Olympus EM1 camera. In my typical lazy fashion all are resized images from the straight out of camera Jpegs.
Lighting for this set was conducted using two UVB bulbs, one an ExoTerra 200, the other a Lucky herb equivalent.

Attached Image: UVB_Visible_200_8_80.jpg

UVB (313bp25 filter stacked with 330WB80improved):
Attached Image: UVB_UVB_800_8_20.jpg

UVA (330WB80improved only):
Attached Image: UVB_UVA_200_8_2.jpg

IR (720nm LP flter):
Attached Image: UVB_IR_200_8_2.jpg

This set is imaged using two 365nm LED lights to show the difference slight in the flower signature depending on the Light and to grab a UV induced IR image. For some reason I didn't take a UV induced visible image. Not sure why. Yes I know I may need to try and white balance these ones better. But I like the false colors.

UVA (Monochrome looking with just 365nm Light):
Attached Image: 365nm_UVA_200_8_8.jpg

Attached Image: 365nm_UVIIRF_800_8_40.jpg

#2 OlDoinyo


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Posted 16 July 2019 - 15:27

Is a 365-nm LED a good light source to use for UVB?

#3 Andy Perrin


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Posted 16 July 2019 - 16:43

No, he is using the ExoTerra bulbs for UVB.

#4 enricosavazzi


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Posted 16 July 2019 - 16:58

It is possible that the main difference between the image in the 313 and 330 nm centered bands is due mainly to a different reflectivity in the two bands, rather than a lower absorption in the shorter wavelength band. The middle portions of the petals in these pictures seem to reflect to a higher degree in the shorter wavelengths, and thereby produce a lighter shade of false-black (or you could perhaps call it dark false-yellow) than the higher wavelengths. The proximal parts of the petals, instead, seem to have a low reflectivity in both bands.
-- Enrico Savazzi

#5 dabateman

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Posted 16 July 2019 - 19:59

View PostOlDoinyo, on 16 July 2019 - 15:27, said:

Is a 365-nm LED a good light source to use for UVB?

Only if you want black images. There is no UVB in a 365nm bulb. The ExoTerra have a very strong 313nm Mercury line that my filter catches.

Enrico, the ExoTerra doesn't have a strong 335nm line so the next strong line is 365nm. That is what I think I am seeing.
I have a 335bp10 filter, so I know have the light behaves.

What drew me to this was not the petals but the tubes that hold the pollen heads. Sorry, my flower anatomy is lacking. In UVA they are clear to yellow. But in UVB they are black. I find that very interesting, and this is the first time I have seen that.

Edited by dabateman, 16 July 2019 - 21:14.

#6 Andrea B.

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Posted 17 July 2019 - 20:46

Nice find, David! Thanks for posting.

Things like this are worthy of further study. It would probably be useful to know what the pigments of this lily are too.

Male: An anther (pollen head) sits on a filament. The combined anther & filament form a stamen.
Sta(y)-men and fila-me-(i)n(t). I want an anther now!

Female: The longest tube in this lily is the style at the distal end of which is the stigma and at the proximal end is the ovary. The combination of stigma & style is the pistil.
The pistil packin' mama sez there ain't no stigma in havin' style.

Ok the mnemonics are fairly lame. But that's how I learned it. :rolleyes: :rolleyes: :rolleyes:
Waaaay back when everyone had heard of "a pistol packin' mama".
No I'm not that old, but my parents knew this song. So did one of my biology teachers.
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Often found hanging out with flowers & bees.