Technical considerations
The viewing glasses
Until Zenit E (included), the SLR are equipped with a simple frosted glass, this frosted is rather rough on the "ancestors", which does not make focusing easy, especially with the standard lens opening to f3 .5.Zenit, Zenit-S, Zenit 3, Kristall, Zenit 3M, Zenit E, Zenit B, Zenit ES, Zenit 4-5-6.
The Start has also a large rangefinder wedge.
From Zenit EM (until 12xp) appears a new frosted glass, covered with a Fresnel lens (to increase brightness). In the center, a microprism area, surrounded by a clear area (not covered by the Fresnel lens).Zenit EM, TTL, ET, 10, 11, 12, 12xp and Zenit 16 and 19.Also Belomo Zenit 130.
Last version, from Zenit 122 and on Automats. At center, a rangefinder wedge surrounded by a ring of microprisms, then a large clear area. The rest covered by a Fresnel lens.Zenit 122, 212k, 312m, 412dx, 412ls, Automats, AM, AM-2, AM-3, APM, APK, KM, KMplus.
The display
From Zenit TTL, the light metering is done through the lens, the display is in the viewfinder. For TTL and 12, a needle moves past marks +, O, -.
Zenit 19 follows the same principle, the appearance is slightly different.
On 12xp and following diodes replace the galvanometer. The upper one indicates over-exposure, the lower the under-exposure, you chose the aperture or speed to be closer to the position of switching from one to another.
Zenit 16 follows the same principle, but the diodes are on bottom...
The Zenit 122 are seen to add a third diode, green, in the middle, to indicate the correct exposure. According to J. L. Princelle, there should be versions of Zenit 122 with only 2 diodes.Zenit 122, 122k, 212k, 312m, 412DX and LS
Belarusians did not have access to the new electronics. Zenit 130 display has only two diodes, but green.
The Zenit Automats also display two diodes, their behavior is different depending on whether they use the Russian or French electronics. See details on pages of Automats.
For Zenit AMs 3diodes.Zenit AM, AM-2, AM-3
Last development on the APK and KMplus: the red LEDs are arrow-shaped.Zenit APM, APK, KM, KMplus