When I saw it in the window of the shop that day, I didn't ask myself if I had enough money on my bank account, I took the cheque book out of my pocket and said "I take it!". 1700f, at that time was more than one month of my salary.
Russar MR-2 5.6 / 20mm
Russar MR-2 5.6 / 20mm with it's dedicated viewfinder, second-hand bought for 1700f on october 15th, 1984
Russar: original optical formula, created in 1935 by M.M.Rusinov, to reduce the loss of light in the edges (vignetting). A lot of photographic lenses are based on this formula. The "russarof" optical formula is the basis of Zeiss Biogon-2, Schneider Super-Angulon, Rodenstock Grandagon and many others.
Adapted from: http://www.zenitcamera.com/archive/lenses/russar-mr-2.html
The mount has no coupling for the rangefinder, it is no use, at F:8.0, the image is sharp from 30cm to infinite. The viewfinder can be tilted to compensate the parallax error for close-up views.