Nikon Eyepiece Cap. D5100 and similar models.

thingiverse

Designed specifically for use with Nikon D5100 cameras but adaptable to other Nikons, as long as the naked viewfinder is roughly 24mm wide across. Simply attach this simple plastic cover over your viewfinder to prevent stray ambient light from creeping in and disrupting long exposure shots. These caps are a lifesaver for photographers working on delicate images, especially when working outdoors during daylight hours. As anyone who has lost count of their accessories will attest, it's incredibly easy to misplace these little gadgets, so instead of wasting money buying them by the dozen, try making one using your home printer instead! With just a basic understanding of how to operate your 3D modeling software, you can whip up this plastic protector in no time. Printing Instructions: Lay your print flat and press "print". This thing prints super quickly. Be sure not to set "raft" when printing this tiny model as it won't affect the strength at all. Go for full detail mode with the option turned on because what is there are going to look so neat with high quality that no matter where the viewfinder might be - inside, outside or elsewhere around here somewhere inside. Use 5 separate print layers in your settings; this gives it enough thickness while saving space as little bit heavy than nothing else really doesn't even feel bad! Remove supports afterwards carefully using something sharp like x-acto knife; that helps secure good quality look throughout edges & seams where required making fit precise overall