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Discussion in 'Black and White' started by tbyork2012, Jun 23, 2013.
Hi. Shot these today.
Macro of cornflower center in UVIVF:
Even closer (very shallow depth of field):
How about this one? The flower had closed down last night, but it has opened up again today.
Beautiful work Boon!
wow, amazing colors!
Very nice Boon, esp the UV one of Calendula!
These are wonderful. I am really curious about how you do the UV induced fluorescence photographs. Any links/info on how to go about it is greatly appreciated. TIA!
(updated: Coreopsis spp. Thanks to Klaus for the ID)
You will need a few things to do this successfully: 1) the correct subject, 2) a UV light source like a 365nm UV torch (this needs to be a more powerful one like the Nichia-chip torch), 3) total darkness so the only light recorded by the sensor is the visible fluorescence from the flower as a result of shining a UV light on it, 4) a tripod to mount the camera as this will be quite a few seconds of exposure, 5) a lens system to do close-up macro shooting.
I do use my modified E-PL5 with a Baader UV/IR cut filter but an unmodified camera will do just fine.
Thanks! I am looking around for Nichia chip torch and haven't been able to find one yet here in the US. Let me look a little harder. I think I can manage the rest :smile:.
Upon further research, looks like Nichia might be available but a little hard to source. However, I came across "blue light" that a lot of divers use for fluorescence videos. Would this light work well for flowers too? Or is it very specific to underwater objects?
You do need a UV torch with minimal visible leak, which is why 365nm is preferable. Those blue light torches (probably centred around 385-395nm) will have some visible light, which will not give true UV-induced visible fluorescence. BTW, I would urge eye-protection when using UV light to prevent damage to your eyes.
There is an even more powerful UV torch Hoplite365 based in USA which is not cheap. The other option is to buy a less powerful (but cheaper) UV torch 3W to 5W and do longer exposures, with higher ISO. BTW, I used 2x 365nm Nichia-chip torches for those shots.
UV illuminated + fluorescence
Defringe gone wrong
I think much of the "effect" is visible light leaks from my illuminator (UG5 glass + G8T5E Ushio bulbs). I did use a polarizer film on the illuminator and a crossed polarizer on the lens (linear polarizers) which does work to minimize the NIR leaks in the UG5 but does nothing for the UV.
Thanks. As this is only for experimentation, I guess I'll get a less powerful/cheaper UV torch and do longer exposures. I might finally get a chance to use the live time mode.
Curious how does one apply WB to UV induced fluorescence as it seems non-sensical! Do you adjust to match by eye or what? I just leave it as shot (AWB) and tweak for aesthetics.
There is no right and wrong to WB for UVIVF. You just need to find the one which you like the most. In the past I used to do a few versions and choose my favourite. Nowadays I just do one version and stick with it. Sometimes I do wish there was more of a particular colour though.