The only real difference between the Zorki-3 and Zorki-3M is all the shutter speeds have been moved to the top dial. The shutter release button on the Zorki-3M also protrudes higher above its collar than it does on the Zorki-3. Most Zorki-3M's have a matt finish but there are some examples where the metal parts are highly polished [2].
Produced: 1954-1956
Name: „Зоркий-3М“
Producer: KMZ
Frame size: 24x36.
Lens: Jupiter-8 2/50.
Shutter: 1-1/25s, 1/50s, 1/100s, 1/250s, 1/500s, 1/1000s + B.
Quantity: 87.569 units (both with Zorki-3). (Sovietcams.com)
5558873 napchop
5565856 David Tomlinson