Anamorphic Lenses

Anamorphic lenses are used to shoot wide-screen movies. All Russian anamorphics are 2:1 ones. It is also necessary to change a film gate in the camera.

All anamorphic lenses and attachments manufactured in USSR and in Western world have same standard optical diagram. Anamorphic attachment is afocal lens system consisting of two cylindrical elements of different focal lengths. It is purposed to change focal length of a lens in one plane.

Such attachment is placed in front of anastigmat lens. It has big dimensions that leads to increase of size and weight of anamorphic block. This basic principle is used to build all range of Soviet anamorphic blocks from F=22mm to F=200mm.

Tele anamorphic blocks have an anamorphic attachment mounted in the rear part of the assembly, and it doubles focal length of the lens. Such design is used in anamorphic blocks OKS4-200-1A, OKS5-300-1A, OKS6-500-1F and OKS3-750A. But rear anamorphic attachment lowers image quality of the lens.

In 1972 in LIKI was designed unique super wide angle anamorphic attachment «Bifocator-2» for OKS1-22-1 (F=22mm, f/1.8) lens. This attachment had 5 elements and view angle 2ω of 105°.

Russian super-wide 22mm anamorphic lens 35БАС26-1 made at NPO "EKRAN" has no match abroad. This lens allows to get acceptable image quality, but it has relatively high distortion (Δy'=-15%) that allows to ease perspective curvature and achieve variable squeezing factor across the frame.

A35mm anamorphic block 35BAS27-1 was designed and made at NPO "EKRAN" in 1973. It has optical diagram with 2-element spherical compensator, 2-element anamorphic attachment and prime lens OKS11-35-1 (2/35mm). This bloc has extended rear focal distance (35mm) that allows using it on cameras with dual shutter system. Disadvantage of this block is 15% higher squeezing ration on edges (comparing with center).But 35BAS27-1 block has numerous advantages in design and light sensitivity. Main feature of this block is ability to focus moving front negative element of the compensator only. Cylindrical attachment and prime lens are immovable that means simplier design improved usability. Also, this provides constant squeezing factor for distance range from 1 meter to infinity.

Anamorphic blocks and attachments for wide-screen shots

Name or code Focal length, mm Relative aperture
Angle of view
Dimensions, mm
Weight, kg
geometrical
effective
vertical
horizontal
length
max. diameter
35BAS26-1
22
1:2.8
1:3.6
39°34'
80°28'
124
124x100
1.80
35BAS12-4-01
30
1:2.8
-
34°38'
72°30'
-
-
-
35NAS10-3
35
1:2.0
-
29°54'
64°18'
-
-
-
35BAS10-2-01
35
1:2.0
-
29°54'
64°18'
-
-
-
35BAS27-1
35
1:2.0
1:2.5
29°54'
64°18'
165
143
3.30
35BAS22-2
50
1:2.0
1:2.5
21°11'
47°30'
162
106
1.60
35BAS23-2
75
1:2.0
1:2.5
14°12'
32°42'
187
106
1.84
35BAS25-1
100
1:2.8
1:3.4
10°42'
24°49'
206
106
1.87
35BAS2-2
150
1:3.5
1:4.2
7°08'
16°42'
255
91
1.65
OKS4-200-1A
200
1:5.0
1:5.8
5°21'
12°34'
168
55
0.32
OKS5-300-1A
300
1:5.0
1:5.5
3°34'
8°24'
174
66
0.84
OKS6-500-1A
500
1:5.5
1:5.9
2°08'
5°02'
238
83
1.15
OKS3-750-1A
750
1:6.3
1:6.8
1°24'
3°22'
372
105
2.10

Lenses for wide format shots (for 70mm film)

Name or code Focal length, mm Relative aperture
Angle of view Dimensions, mm Weight, kg
 geometrical
effective
 vertical
horizontal
 length
max. diameter
Kinorussar-10
28
1:3.5
1:3.8
44°36
86°18
109
126
1.00
OKS4-40-1
40
1:3.0
1:3.6
32°04
66°33
79
77
0.42
OKS5-56-1
56
1:2.5
1:2.8
23°12
50°14
47
58
0.19
OKS4-75-1
75
1:2.8
1:3.2
17°26
38°35
44
56
0.12
OKS2-100-1
100
1:2.8
1:3.4
13°08
29°05
86
66
0.56 (in the mount)
OKS2-150-1
150
1:2.8
1:3.2
8°46
19°51
118
76
0.88
OKS1-200-1
200
1:2.8
1:3.2
6°35
14°58
124
106
1.30
OKS1-300-1
300
1:4.5
1:4.0
4°23
10°00
147
121
2.03
OKS4-1000-1
1000
1:11
1:12.2
1°19
3°00
520
142
4.90


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