Andy Perrin Posted January 17, 2021 Share Posted January 17, 2021 Here is a pumpkin (or in some parts of the world, a squash) using Laser-Stimulated Fluorescence (LSF). LSF was described in my first post on it back here. Please reference that post for the procedure and background, safety requirements, and equipment used. Camera was the Sony A7S (modified).Lens was the Nikkor 20mm/3.5 (which I haven't tested in UV reflectance).Filters on camera were the Tiffen Haze 2E + BG38 2mm. 30 sec, F/16 (for depth of field reasons), ISO400.White balance altered to suit taste. Link to comment
colinbm Posted January 17, 2021 Share Posted January 17, 2021 That seems to be working well Andy.I wonder if you had two lights working in parallel, either side of the lens, you would get less shadows. Link to comment
Andy Perrin Posted January 17, 2021 Author Share Posted January 17, 2021 Thanks Steve! Colin, my big problem right now (aside from figuring out how to attach one of those Powell lenses which is turning out to be very hard) is that the light painting is hard to do without leaving bright lines by lingering too long in one spot. I badly need to automate the scanning process with a turntable setup. Dealing with two lasers at once is a problem for some other day! In this case I actually like the shadows though. Link to comment
colinbm Posted January 17, 2021 Share Posted January 17, 2021 Yes I appreciate the shadows give depth & 3D... Link to comment
otoien Posted January 17, 2021 Share Posted January 17, 2021 +1, and then there is that almost toothless face in there. Link to comment
dabateman Posted January 17, 2021 Share Posted January 17, 2021 Great composition Andy.Also nice your pumpkin hasn't gone moldy. I assume its not leftover from Halloween. Link to comment
Stefano Posted January 17, 2021 Share Posted January 17, 2021 Nice colors. It would be interesting to see if typical UVIVF yields weaker colors. Link to comment
JMC Posted January 17, 2021 Share Posted January 17, 2021 Very nice Andy. Looks like a useful approach. Link to comment
Andy Perrin Posted January 17, 2021 Author Share Posted January 17, 2021 dabateman actually it really is leftover from Halloween. It never rotted so I never threw it out. Stefano I actually shot a UVIVF also but it’s very similar. Colors are slightly bluer. The intensity isn’t making much difference to the results here because the pumpkin already glows pretty strongly in UV. Link to comment
Andy Perrin Posted January 17, 2021 Author Share Posted January 17, 2021 Here's the UVIVF: Here's the LSF again for comparison purposes so you don't have to scroll: Link to comment
Stefano Posted January 17, 2021 Share Posted January 17, 2021 I think the LSF has nicer colors. Changing the exitation wavelength can change the emitted colors. Link to comment
bvf Posted January 17, 2021 Share Posted January 17, 2021 That is amazing! Hope you enjoy your pumpkin pie. Link to comment
Andrea B. Posted January 21, 2021 Share Posted January 21, 2021 There is a beautiful unexplored jurassic-jungle-world in there. Dinosaurs might be encountered. An interesting aspect photographically is the cool reflection (perhaps off aluminum foil?) underneathwhich gives the impression that the pumpkin is glowing from inside. Link to comment
Andy Perrin Posted January 21, 2021 Author Share Posted January 21, 2021 Yes, it's sitting on aluminum foil, in hopes of reflecting more light inside so it's not all dark. Link to comment
Andrea B. Posted January 22, 2021 Share Posted January 22, 2021 Andy, you have a good compositional eye in case I haven't mentioned that before. For about a year I have been quite lazy about making any UVI fluorescence photos. They can be so cool and dramatic and interesting. Link to comment
ulf Posted January 23, 2021 Share Posted January 23, 2021 I really like these images and their composition. I wish I too had time and locations suitable trying UVI fluorescence photos. Andy, what is the reason for using a laser instead of a high power LED with 405nm?The line laser idea makes my design mind literally spin with ideas of how to get some scanning of the line over the motif.I am tempted to get a line laser and do some proof of concept tests of my ideas. Link to comment
Andy Perrin Posted January 23, 2021 Author Share Posted January 23, 2021 Ulf these are proof of concept tests for large scale fluorescence on the sides of buildings! I want to do fluorescence at the 10m scale. I’m actually already working on a turntable idea with a stepper motor. Also- line lasers with cylinder lenses are a bad choice for this actually. Powell lenses are a must. Check the paper I linked on the original topic here:https://www.ultravioletphotography.com/content/index.php/topic/4293-laser-stimulated-fluorescence-first-tests/ Link to comment
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