Center Pinch Camera Lens Cap

Once upon a time I decided that getting into film photography is what I want to do next with my life, as such I bought a used Canon EOS 300V. Upon arrival I noticed the seller hadn't included a lens cap. Instead of buying one like a boring person I designed this little thing.

I designed the finger wells to accommodate my sausage fingers and I can comfortably squeeze the 58mm model (your mileage may vary with smaller models and the calibre of your fingers)

The actual diameter of the cap is 1.5mm smaller than the declared diameter since I noticed that even though my lens claims to be a 58mm, the inner diameter is roughly 57mm.

Due to the fact that all of the different sizes are just scaled up/down in the XY planes from the same model you may find the tolerances aren't tight enough on the bigger models in the middle of the mechanism and it can move up or down. This hasn't bothered me but you can remedy this with good ol' super glue.

Printing

Print it in any material you please, orient the pieces flat side down (the other side has a curve to accommodate slightly protruding glass that some lenses have). Also remember to create a second instance of the grip piece (using the ‘+’ button at the top if you're using PrusaSlicer, only one STL file is included because they're identical)

Assembly

To put it together just slide in the grip pieces like this:

The result should look like such:

The next step is to squeeze and enjoy, happy printing!