Continuing the rangefinder equipment reviews following my previous review of the Epson R-D1s, I'll be diving into lenses for the system. The Jupiter-12 is a very peculiar lens, as it is a copy of a 1930's Zeiss lens, the Zeiss 35mm f/2.8 Biogon for the Zeiss Contax rangefinder camera produced in Jena, Germany. Following WWII, and the division of Germany, Russia received the Zeiss factory located in Jena, resulting in the acquisition of Zeiss camera and lens designs. My copy of the this lens was produced by LZOS in 1973, and was produced for export as shown by the Roman characters as opposed to Cyrillic Script.
The build quality is good. It's an all metal and glass construction with a very smooth focus ring (even though it is quite small!) Here's where it gets interesting. The filter ring is actually how you set the aperture. It can make it a little slow at times having to look at the front of your lens to change the aperture, and sometimes it's easy to forget what aperture you've set. The aperture ring is de-clicked meaning you actually have to look at it when making changes.