Initially the factory was managed by the head of the commune Anton Makarenko and produced simple electrical machinery (drills).
The FED-3 added slow shutter speeds and on the later version FED-3 (b) the film advance was changed from a thumbwheel to a lever.
During World War II production was shifted to Siberia as the factory in Kharkiv was overrun by Nazi German forces.
During this period and immediately after the war some serial numbers between 174000 - 180000 were used on cameras built in Berdsk in Siberia, even in the first few months of 1946.
On Leica bodies they will not focus to infinity and the rangefinder will not be accurate, resulting in unsharp images.