The Russian Jupiter-8 is a high quality normal lens for the Leica Threadmount rangefinder cameras. It was sold as a standard lens on many cameras - Zorki-3, 3M, 4, 4K, Leningrad, Drug and some others. This lens is a copy of a famous Zeiss Sonnar 50/2.

It was produced in both LTM and Contax/Kiev mount and proved to be one of the most successful Soviet lenses. Of course, we have to credit Carl Zeiss for this.

Focal length: 52.3 mm
Aperture: 1:2 (settings from 4 to 22)
Focusing: 1 m - infinity
Filter size: M40.5x0.5 mm
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.)

The glass is coated; the barrel has a polished aluminum/chrome finish

(Source: www.fedka.com)