It seems to be a lens for 16mm film, but my reference book states that it is for 35mm film.
Manufacturer | "OPTON" (Germany) | |
Lens system | - | |
Focal length | f' | 25.9 mm |
Angle of view | 2ω' | 57°06' |
Effective relative aperture | f:nэ | 1:1.4 |
Lens length | Σd | 78 mm |
Front focal length | S | - |
Back focal length | S' | 27.2 mm |
Flange focal distance | Z | - |
Block length | B | 88 mm |
Block max. diameter | D | 76 mm |
Rear diameter | D' | 41 mm |
Front element diameter | d1 | 47.5 mm |
Rear element diameter | d2 | 27.0 mm |
Mount thread | - | |
Distance from rear end of the housing to the focal plane | l | 26.2 mm |
Aperture blades quantity | ? | |
Frame size | 16x22 mm | |
Weight | 550 g |