I have a Nikon N8008s w/ a round rubber eyecup on it. It looks like this: http://www.bhphotovideo.com/c/product/37450-REG/Nikon_2925_Finder_Eyepiece_for_FM.html The eyecup shown may not be exactly like mine, but you get the idea. Just a round donut with, I think, threads. Nikon made about a million different rubber eyecup designs, but this one is the smallest and the simplest. I thought it would just unscrew, but no go. I would like to get it off and clean inside. It will unscrew about 1/4 of a turn, and then stops. I tried pushing in and turning, pulling out and turning....nothing. Any ideas? The camera came from KEH w/ the eyecup already on it, but I'm pretty sure that the camera eye hole has threads, and this piece just screws on. Thanks.