Helios 44 & 44-2
Helios 44-2 2.0/58mm, bought with my first Zenit E on july 18th, 1978. And others...
It is with Industar 50 the standard lens for the Zenit cameras, before the arrival of coupled diaphragms.
Helios 44 2.0 / 58mm, delivered with the Zenit 3M on July 18th, 2009.
According to it's serial number, one of the first models for Zenit, in M39 mount (1960?) (already existed in "Start" mount since 1958).
Helios 44 2.0 / 58mm for Start, delivered with the Start on May 18th, 2010.
Optical body similar, but different mounting: the helical and the focusing ring are towards front, diaphragm control towards the camera, allowing a semi-automatic control: the iris closes when you press the button, which itself pushes the shutter-release button.
A "manual" position is provided, for use of the self-timer or macro, by turning the button: At left, one point opposite the fixed point: automatic. At right, two points: iris closed.