This is a rare rigid version of a well-known Industar-22 lens. I was made in small quantities in the early 1950's and was sold with export models of Zorki. Optically it is identical to the collapsible Industar-22, but has a unique mechanical design.
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 aluminum, matte chrome
(source: www.fedka.com)
Measured weight: 94g. (serial # 5203599, Jacques M. coll.)