First, numberless Zenit, also sometimes called as "Zenit-1". Produced 39.019 pcs in 1952 - 1956. Camera in pictures is a 1954 and with wrong, later lens. Prototypes and preseries had slightly different top plate or name plate. Based on Zorki rangefinder camera, bottom film loading
Differences to Zenit-S:
Mirror is returned with film advance after picture taking.
No flash sync.
Shutter speed knob is full, no center index mark. Speeds 1/25, 1/50, 1/100, 1/250, 1/500 and B.