Industar-51
The Industar I-51 was a large format 210mm f4.5 lens. A solid piece of optics made by KOMZ in Kazan, often found on FKD 13x18cm large format view cameras. It had a 20-blade aperture to stop down from f4.5 to f32 with round opening at all sizes.
Links
- discussion on APUG [1]
- military version on USSRPhoto.com [2]