PK5650. Prototype 35mm camera for full frame stereo pairs, with the switch on the top plate for selecting MONO. Centered viewer with projected frame lines, selenium meter needle indicator, and pendulum horizon indicator in the center, all projected using the van Albada type viewer. Single lever wind and cocking mechanism for both shutters. Frame counter, individual shutter speed selectors. The shutter/lens assemblies come from the Voskhod.Shutter releases and diaphragm settings coupled between the lenses. Individual focusing of the two T-48 2.8/45mm lenses. 75mm interlens distance. Accessory shoe. Contax-type removable back with adjustable pressure plate. Built-in film cutter like the Exakta (source: J.L.Princelle "The Authentic Guide to Russian and Soviet Cameras", 2nd edition).
Camera below from private collection in Europe.