Olympus 12-40mm lens cap with bayonet fitting for filters

thingiverse

I have a few custom filters for my 12-40 (62mm Ø) that are threadless, which means I can't use the standard lens cap when one is in place. To solve this issue, I designed a filter cap that fits over the lens's bayonet mounts and any attached filters less than 7mm thick. I'd print it out of a flexible plastic material like PLAFlex or PETG. This design relies on a small lug to secure into position, so a somewhat pliable plastic is required. I wouldn't recommend using PLA as it's quite stiff and has a relatively high surface hardness, which could cause wear on the camera's bayonet lugs over time.