Zeiss Sonnar 5.0cm f/2.8 COPY
The Jupiter-8 (sometimes marked in Cyrillic, ЮПИТЕР-8) is a postwar Soviet copy of the prewar Zeiss Sonnar 50mm f/2 for the Contax, built with six elements in three groups. It was made in Contax and M39 mounts, both for rangefinder cameras.
Without a doubt the strength of the lens is the image quality. Soviet optical factories were known for sharp optics, and this one is no exception. The edges are not so good but the center is.
The lens was originally available only in the natural rather dull "silver" of aluminum but in the 1970s was also made with a black finish. It belonged to the Soviet class of lenses which was named Jupiter.
Description
Focal length - mm 52 Geometrical relative aperture 1:2
Corner of a field of vision: 45 ° The size of a shot: 24x36 mm
Quantity of lenses/groups: 6/3 Forward topmost focal length: −49,60 mm
Back topmost focal length: 27,75 mm Distance from the first to last surface: 31,74 mm
Light diameter of the first surface: Ø29,0 mm Light diameter of last surface: Ø22,0 mm
Resolution (0mm/10 mm mm/20): 39/29/24 lines/mm Resolution on THAT (centre/field): 30/14 lines/mm
Enlightenment type: chemical, single-layered Limits of a scale of diaphragms: 1:2 - 1:22
Near limit of focusing: 1 m Working distance: 28,8 mm
Lens with the camera thread : M39x1 Weight: 130 gr
Aperture works throughout the range, the lenses with light cleaning marks. No dust inside. Focusing Ring rotates smoothly . Outer cage in used condition - traces of age - look pictures - it is actual.
The diaphragm blades are clean.