Jupiter-8 (Юпитер-8) lens is a popular Soviet/Russian-made copy of a Zeiss Sonnar 50/2. Focal length: 50 mm Aperture: 1:2 (steps from 2 to 22) Focusing range: 1 m - Infinity Filter size: 40.5x0.5 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 lens is finished in black - later production version made from mid-1960's to the production end in the late 1970's. The glass is coated. The lens is in EXC/EXC+ condition, clean glass, clean exterior. The focusing is smooth. This Jupiter-8 comes with generic front and rear caps. The lens is shown mounted on a Leica II (camera is for illustration only and is not included). Jupiter-8 is a great fast prime lens, it can be used on any Leica (or Leica copy), thread mount or M mount (with an adapter). It is also a popular choice for a prime lens on many mirrorless cameras, Micro Four Thirds, Sony Nex, and others. A variety of adapters is available.