The OKS5-250-1 lens is purposed for usual film shots.

Manufacturer NPO "EKRAN"
Lens system -
Focal lengthf'250.0 mm
Angle of view2ω'6°12'
Effective relative aperturef:nэ1:2.9
Lens lengthΣd110.6 mm
Front focal lengthS-
Back focal lengthS'151.5 mm
Flange focal distanceZ-
Block lengthB230 mm
Block max. diameterD135 mm
Rear diameterD'-
Front element diameterd189.5 mm
Rear element diameterd256.5 mm
Mount thread -
Distance from rear end of the housing
to the focal plane
l-
Aperture blades quantity ?
Frame size 16x22 mm
Weight 3.1 kg