Early silver Grand Prix Brussel Mir-1 2.8/37 wide-angle lens M39/M42 mount SLR

Focal length - 37 mm

Angle of view - 60º

Maximum aperture - f2.8

Minimum aperture - f16.0

Closest focusing distance - 0.7 m

Mount thread - M39/M42x1

Thread for attachments - M49x0.5

Resolving power, lines/mm: in centre - 45; off centre - 23