A lost lens cap is a standard part. The number next to the ⌀ sign on the lens front (52, 58, 67, 77 mm…) is its filter thread, and that one number sizes a cap that snaps in like the original. Lenses without a thread get a slip-over cup sized to the barrel or the hood.
Free and without an account: pick the size, check the fit in the live section, download STL and 3MF files that Bambu Studio, OrcaSlicer and PrusaSlicer open directly. Put the focal length or a logo on the front in a second color, add a strap holder for up to three caps, and print the fit-test ring first if you are unsure.
It is printed on the lens front or inside the old cap, next to the ⌀ sign. A filter you already own carries the same number on its ring.
Push-in grips the filter thread, so it also fits on top of a screwed-in filter. Slip-over is for lenses with no filter thread, or to cap the lens hood.
The skirt only enters the thread, 3 mm by default. On lenses whose glass sits close to the thread, lower the skirt height.
Your exact configuration is attached automatically, so the bug can be reproduced one-to-one. No account needed.
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