This is a half frame viewfinder camera with manual override. Focusing is by distance scale on the lens or symbols in the viewfinder. Shutter speeds are visible in the viewfinder as is a parallax frame for close-ups. The back is removable and the camera has a jack for flash but no accessory shoe. There is also a very rare version with white fabric and another commerative with a "60 years of the USSR" issued in 1977 and the olympic edition.
The very first production was different it had rounded corners and a fixed door wrapped around the bottom. Mikron was in script letters on the front with FED on the top. These cameras are very rare and represent a pre-production batch. It has a soft black vinyl zippered case (source: http://www.commiecameras.com).
Camera was pretty expensive, it sold for 85 rybley. Monthly earning for many in USSR at that time. FED Micron price is almost twice as much as FED3. Probably because it was new technology at that time.
Name: „ФЭД Микрон“
Frame size: 18x24
Lens: Helios-89 1.9/30.
Shutter: 1/30s-1/800s + B.
Quantity: ±120.000 units.
Original price (in year 1986) 85 roubles. (Sovietcams.com)