It offers a number of improvements over the original Zorki, including a large combined viewfinder with the rangefinder builtin, a removable back, and a larger and faster Jupiter-8 (lens) (Zeiss Sonnar copy) lens. It also adds a new mechanism for slow shutter speeds with a separate selector dial on the front of the camera. This mechanism was unreliable, so the improved Zorki 3M of 1954 (also produced in 1955) combines all of the shutter speeds on a single dial.