I stopped using my Zorki 4 because when wearing glasses, I cannot see the edges of the viewfinder. Gives a 80mm focal length view. The viewfinder opening is a little too small to make a nice diopter adapter. I was not able to find a reasonably priced accessory viewfinder with a 50mm focal length field of view. I wound up getting a Bessa R4M that accepts Nikon diopters. If you can get your eye right up to the eyepiece you should be OK in terms of field of view for the 50mm lens.