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Discussion Starter · #1 · (Edited)
Hi, all! I've been absent from the forum for a while, working on a novel and helping my wife create pollinator habitat at our HOA. Plus, I've just committed myself to Master Naturalist training, and they've been looking for a techie to work on a bee vision project. Since I already had an interest in this very thing, it lit a fire under me.

The key to this project is a UV-pass filter (blocking visible light almost totally). I got a flyer from Marlin P Jones Associates (MPJA) about a week back that was showing these for about $9.95 each, Previously I'd seen such filters priced at over $200, so I figured I just had to avail myself of these. I bought three, and they arrived today. They look like 42 mm diameter black plastic disks. They are supposed to pass 365 nm UV.

I put an old 50mm lens on my Nikon D5100, chosen for this project a couple of years ago as expendable in case I needed to remove any coatings, and it has fewer pieces of glass than my zoom lenses. I slapped one of the filters over the lens, switched the camera to video, and watched the resulting image on the camera display. Indeed, it showed both my longwave (405-ish nm) and my 365 nm UV flashlights easily, when a desk light barely produces a dull glow thru the filter.

Then I created an artificial flower from a piece of white paper (should contain titanium dioxide which reflects UV nicely. The paper shows when illuminated with the flashlights. Finally, I grabbed some sunscreen and painted a circle on the paper. Sunscreen typically shows as black in UV photographs. Indeed, the image now showed the black spot.

That's all it takes!

This should work with most cameras as long as you remove any UV blocking filter. Possibly some plastic lenses will block UV, but I suspect most cameras, especially cheap webcams and USB cameras, will work.

These filters are un-mounted, so I will either use a filter adapter and some glue or cut a hole in a lens cap to mount one.

If you want to do such a project, MPJA has 17 of these left as I type this.

35587 MI 365nm UV Pass Filter 42mm Diameter 3 $29.85
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