Before ZENIT E

For me, photography really began with the Zenit E, but this camera did not appear on earth by spontaneous generation, it has ancestors... The production figures cited here come from KMZ.
You can find details by year, on http://www.zenitcamera.com/catalog/cameraproduction.html.

Zenit (1): 39019ex. produced between 1952 and 1956.
Take a Zorki (1), add a mirror and a pentaprism, the Zenit is born!
Zenit-S: 232949ex. between 1955 and 1961.
The Zorki became Zorki-S, with the addition of a flash-synchro, the Zenit becomes Zenit-S with the same assembly. The mechanism of descent of the mirror, too fragile, is replaced by a rope and two pulleys.
Zenit-3: 81776ex. between 1960 and 1962.
The cocking button is replaced by a lever, a new cover encloses the whole top.
Kristall: 65433ex. in 1961 and 1962.
On the basis of Zorki 6, emergence of the hinged back, so far the cameras were loaded "Leica way", by the sole.
Shutter release on the axis of the cocking lever and rewind button are those of the future Zenit E. Top cover in painted metal.
Zenit-3M: 781678ex. between 1962 and 1970.
The curious Kristall top cover was not really liked ... It is replaced by a chrome cover very similar to that of the Zenit-3, The name "Zenit" comes back for good.