LOMO OKS7-28-1 (2/28mm)

The OKS7-28-1 lens has extended back focal length of 32 mm. Optical construction is complex system consisting of 9 elements grouped into 7 components. Image quality corresponds to early OKS4-28-1 lens, bat OKS7-28-1 lens has longer back focal length.

Specification of LOMO OKS7-28-1 optical block 
Manufacturer
NPO "EKRAN"
Lens system

-
Focal length
f'28.0 mm
Angle of view2ω'51°50'
Effective relative aperturef:nэ1:2.3
Lens length
Σd43.3 mm
Front focal lengthS-
Back focal lengthS'31.5 mm
Flange focal distanceZ
41 mm
Block length
B45 mm
Block max. diameter
D45 mm
Rear diameter
D'SpM 33x0.75
Front element diameter
d131 mm
Rear element diameter
d2
18.5 mm
Mount thread

SpM33x0.75 cl 2a
Distance from rear end of the housing
to the focal plane
l
32.5 mm
Aperture blades quantity

12 ?
Frame size

16x22 mm
Weight
130 g