Hard Cover for Nikon (APS-C) DSLR Viewfinder

thingiverse

There are situations where you need to cover the viewfinder during extreme long-time exposure on your DSLR, so as to prevent leakage of light. A simple cardboard will do the job too, but a easy-to-open cover is much better. To assemble the Hot-Shoe Mount and the Cover together, you need an M3 screw and a nut, the more you tighten them, the harder the cover flips. You may also apply a Matte Black Sticker on the Cover to reduce light reflection, if you are running out of Black filament like me.