Figure 18. 120m mag
5.7.3. Lenses
The lenses are shown at the Figure 19. They are complex optical systems purposed for projecting of the geometrically correct
image to the film.
18mm and 28mm lenses are used to shoot a tool and wide objects, landscapes, indoor shots etc.
40mm lens has a general purpose.
75mm, 150mm, 300mm lenses are used for nature shooting of distant objects, hard-to-reach objects, indoors, macro shootings,
and if it is impossible to get close to an object.
The lenses consist of the optical units in focusing mounts. The mount consists of the focusing mechanism (moving the optical
unit along it’s axis) and aperture control. Both focusing ring (140) and aperture ring (141) have stopping devices.
Stopping device of the aperture ring is spring-loaded metal ball stopping the ring in selected position.
Stopping device of the focusing ring is special screw pushing the movable ring by means of the friction element.
The focusing mechanism of 75mm, 150mm, 300mm lenses is spiral groove with dowel moving in it.
The lenses has the light filters YB-17, OB-12, and RB-11. Specifications of the lenses are listed in the Table 8.
Table 8
Parameter
Focal lengths, mm
18
28
40
75
150
300
Allowed error in focus distance, %
2
2
2
2
3
3
Relative aperture
1:2.8
1:2.5
1:2.5
1:2
1:2.8
1:3.5
View angle, °
76
53.4
40
20.6
10
5.7
Aperture range
1:2.8–1:16
1:2.5–1:16
1:2.5–1:16
1:2–1:16
1:2.8–1:16
1:3.5–1:16
Light transmission factor
0.75
0.80
0.75
0.75
0.72
0.90
Flange focal length, mm
57
+0.01
Lens mount
4-ears bayonet
Summary of Contents for GLADIOLUS
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