The Industar-22 design was "borrowed" from Leitz Elmar. It was an improved version of a prewar collapsible FED lens (also known as Industar-10).
The Industar-22 was a standard lens on the early Zorki cameras (Zorki, Zorki-S, some of Zorki-2S') and was also a popular enlarger lens in the USSR in the 60's.
Technical Characteristics
Focal length: 50 mm
Aperture: 1:3.5, settings from 3.5 to 16
Angle of Coverage (35mm film): 45°
Focusing: 1 m - Infinity
Filter size: 36 mm slip-on type
Optical Design: 4 elements in 3 groups, click to see drawing
Optical registration (back focus):28.8± 0.02 mm
Mount: M39x1 mm (LTM). The lens mounts and RF couples with any Leica or Leica copy (FED, Zorki etc.)
Glass: Coated
Finish: Polished chrome, Matte chrome