The 3M-7 300 mm f/ 5.6 (Russian: "3М") is a telephoto mirror lens for 35 mm SLR cameras with M42 screw mount. The lens features an achromatic multicoating.
The lens came in two modifications manufactured at optic glass factories in Lyktarino and Azovsk (LZOS and AOMZ, respectively). The AOMZ variant features:
minimum focusing distance - 1.7 m;
smaller dimensions - 73x78 mm (against 76x81 mm)
There is no reliable information on serial production of this lens.
Links to online resources:
Posted by: dgr Date of publication: 07.04.2012