colinbm Posted April 28 Share Posted April 28 UVA IVF of a Sunflower. Trying out some UVA light mixing with visible fluorescence. Sigma fp full spectrum converted, UV Nikkor 105mm lens with a Zeiss T* UV block filter on the lens. Behind the flowers is a sheet of white PTFE. Four different UV LEDs were used to excite the fluorescence in the cultivated Sunflower, 308nm, 340nm, 365nm & 390nm LEDs. I set-up the four LEDs in a frame & aimed them each at the centre of the Sunflower. Unfortunately the focus must have got bumped as I progressed. The first four photos are of the individual wavelengths, then a combination with all four LEDs exciting the Sunflower to fluoresce. Lastly a directors view of the set-up. PS you can get some wild colours by clicking around with the White Balance picker ! 308nm LED exciter.... 340nm LED exciter.... 365nm LED exciter.... 390nm LED exciter.... Combined all four, 308nm, 340nm, 365nm & 390nm LEDs to excite UVA VFL. The Directors view ! Link to comment
Foxfire Posted April 28 Share Posted April 28 Nice sequence! I am confused that the 308nm and 365nm exitation makes the tips of the flower petals darker than 340nm "light". Something to do with a White Balance picker? Link to comment
dabateman Posted April 29 Share Posted April 29 Colin these are interesting. I wonder if you have some IR leakage in the 340nm image. Where are your Fp monochrome images? I ran out of time today to photograph a couple mini pepers in UVc. I think Andy wants to see some sugar that I will have to chip out. I might only have brown sugar though. Link to comment
colinbm Posted April 29 Author Share Posted April 29 Thanks Dave I'll look into the 340nm LED. I have got some different salt & sugar to to photograph in UVC. Link to comment
photoni Posted April 30 Share Posted April 30 well done @colinbm the results are amazing I would like to understand better what happens. Do 390 LEDs only excite yellow-green? Do 340 LEDs only excite warm tones? Will this also be the case for other flowers/fruits? Thanks Toni Link to comment
colinbm Posted April 30 Author Share Posted April 30 @photoni that is funny ! Short answer is....I don't know ! I know that it happens & I can photograph it. I do know that the light is exciting an electron in an atom to change its energy state & to release a photon. I do need to look at this again closely as Dave has indicated their might be a problem with the 340nm one ? I do know that moving the WB picker around the photo can make for some wild colours. I tried to use the same place on the PTFE background to keep the WB consistent. Link to comment
Alaun Posted April 30 Share Posted April 30 A general question comes to my mind: How is this effect influencing the bees perception of flowers? Link to comment
Stefano Posted April 30 Share Posted April 30 Fluorescence is much weaker than the visible light intensity in sunlight (you don't see sunflowers "glow" under normal sunlight illumination), so I think the influence is negligible. Nectar guides visible in reflected ultraviolet are instead much more noticeable (if you have UV vision). Link to comment
colinbm Posted May 1 Author Share Posted May 1 @Alaun I am not not great believer in this 'Bee Vision' idea. It seems to be laboratory driven & not real life ? Link to comment
Yves W Posted May 1 Share Posted May 1 I think problem WB, the vase is pink on the 340 Link to comment
colinbm Posted May 1 Author Share Posted May 1 @Yves W Yes I agree. I have done these again, except the combining of the lights. Link to comment
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