Quick-Change Magnetic Lens Filter System (49mm)

thingiverse

I just got into Trichrome photography, where you take multiple photos of the same subject using black & white film and red, blue, and green filters, and combine them into a final color image. Unscrewing and re-screwing filters so frequently got old fast. I wanted to be able to switch them out more quickly. This is a friction fit system, so I used TPU as it can get a solid grip on the lens and filters without damaging anything. I expect the design could be successful with PETG and possibly even PLA, as long as the prints were sized exactly right. It uses three 6x3mm neodymium magnets for each component (filter holders and lens mount). Be careful aligning the poles properly when supergluing into place. I had no trouble printing without supports even with the STLs in their native orientation with the magnet holes touching the build plate. It's only a 6mm bridge. If you're worried, try turning fan speed up before resorting to supports. You may find that you need to print these anywhere from 98% to 102% scale depending on how well your printer is tuned, how thick your filter bezels are, etc. Having proper tolerances is key for a friction fit. For the lens mount, I recommend erring on the side of too large, while the filter holders should err on the side of too small. Finally, I use an Olympus camera an OM-mount lenses for my trichromy shots, and all my lenses use 49mm filters. I realize that's not a super popular filter size these days, so if you want to remix for a larger filter diameter, I have included the blender file. Should be able to basically just scale up, but you'll have to go back and scale the magnet holes back down if you want to use 6x3 magnets.