Many operators use OKS1-100-1 (2/100mm) lens. But this lens has not very high image quality. That is why it is recommended to use OKS2-100-1 lens (2.8/100mm) purposed for 70mm film but having different focusing mount and smaller front element. Such lens was named OKS2-100-2. It has higher image quality and is used in anamorphic block 35BAS22-2 as well.

Unfortunately, this lens version is relatively rare. I had only couple of them.

Manufacturer NPO "EKRAN"
Lens system -
Focal length
f'99.7 mm
Angle of view2ω'15°30'
Effective relative aperturef:nэ1:3.2
Lens lengthΣd75.9 mm
Front focal lengthS-39.4 mm
Back focal lengthS'57.8 mm
Flange focal distanceZ90.5 mm
Block lengthB85.5 mm
Block max. diameterD54 mm
Rear diameterD'38 mm
Front element diameterd137.8 mm
Rear element diameterd228.3 mm
Mount thread -
Distance from rear end of the housing
to the focal plane
l51.3 mm
Aperture blades quantity ?
Frame size 16x22 mm
Weight 320 g