FK-Anastigmat 3.5/50mm first Soviet Prototype lens

In 1931, the GOI factory was exclusively focused on the production and development of scientific instruments, such as microscopes and telescopes, and had not yet ventured into the manufacturing of photographic lenses. At the time, a small factory known as Petrograd Optical Plant No. 19 (GAU), which specialized in rifle scopes, received an order from the GOI factory to develop a Soviet-made 50mm lens, similar to the Leica Elmar type.

The GAU factory had already produced the inner lens mount, along with the iris diaphragm and its setting lever. However, it had not yet developed its own external lens mounts and helicoids. As a result, components from the Leitz Elmar lens were utilized in this early experimental phase.

This prototype is one of the earliest Soviet 50mm lenses designed for the VOOMP Pioneer and Geodeziya FAG cameras. To date, only two other lenses of the same design are known to exist, bearing serial numbers 08 and 10. This particular lens, marked as No. 4, was possibly tested on Camera No. 109.