Lens Specifications
Optical design: Tessar (4 lenses in 3 groups)
Optical design Nidustar-61
Precise FR: 52.42 mm
Specification resolution (center/edge): 44/30 lines/mm
Aperture: 6 round blackened blades
Thread for filters: 40.5 * 0.5 mm
Production: from the 70s to the 90s at the FED plant
Main characteristics of Industar-61 L/D 2.8/55
Focal length: 55mm
Max. aperture: f/2.8
Min. aperture: f/16
Optical design: 3 elements in 4 groups
Petals: 6
Filter thread: 42mm
Dimensions (length x diameter): 48 mm x 42 mm