Specification of LOMO OKS 2-100-2 optical block
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 view | 2ω' | 15°30' |
| Effective relative aperture | f:nэ | 1:3.2 |
| Lens length | Σd | 75.9 mm |
| Front focal length | S | -39.4 mm |
| Back focal length | S' | 57.8 mm |
| Flange focal distance | Z | 90.5 mm |
| Block length | B | 85.5 mm |
| Block max. diameter | D | 54 mm |
| Rear diameter | D' | 38 mm |
| Front element diameter | d1 | 37.8 mm |
| Rear element diameter | d2 | 28.3 mm |
| Mount thread | - | |
| Distance from rear end of the housing to the focal plane |
l | 51.3 mm |
| Aperture blades quantity | ? | |
| Frame size | 16x22 mm | |
| Weight | 320 g |
