Type Resolving power value: radial/sagittal, 
Objective of ¡mm -1 for angle of view 
film 
! , 
0 
10° 
20° 
30° 
40° 
i 
1 0 
1 in 
1 
1 
48° 
Medium 
RUSSAR- 
T-3 8 
; 125 
121/123 
110/118 
94/108 
70/96 
62/88 
46/80 
90/102 
71 
N 6730 
T-42 
118 
102/117 
74/99 
63/83 
49/72 
42/68 
35/57 
69/83 
RUSSAR- 
71 
N 6731 
T-38 
125 
121/123 
110/118 
94/108 
73/96 
62/88 
46/80 
90/102 
T-42 
118 
108/110 
74/88 
63/77 
49/68 
42/66 
35/60 
70/78 
The shutter has the exposure range of 1/40 to 1/800 s. The se 
lection of exposure providing for best integral density of nega 
tives is effected by automatic exposure control (AEC), which oper 
ates depending on land illumination, air survey film light sensi 
tivity and multiplication index of light filter of the shutter 
drive and selects the revelant exposure within the available range 
and for maximum relative aperture 1:6,8 or influenced by land illu 
mination, changes relative aperture to the second position 1:9,5. 
So, the AEC can guide the illumination changes up to 40 times. 
One of outstanding features of AFA-TK-10/18 camera in comparison 
with the previous generations of topographic air survey cameras is 
the F.M.C. device. The compensation of longitudinal displacement is 
made by movement of pressing cassette table together with the air 
survey film pressed to it, along the moving frame at a speed equal 
to the speed of land image displacement in the surface of moving 
frame in the exposure moment. The speed of compensation movement is 
within the limits of 2 to 30 mm/c and is set automatically by a 
signal coming from electronic control device EKP-3 and is propor 
tional to the ratio between the survey altitude and flight speed 
(W/H) multiplied at the focal camera length. 
In the process of compensation movement of air survey film and 
in the moment of taking the picture eight fiducial marks are 
printed in the film. The fiducial marks are situated along the mov 
ing frame of air survey camera (in the corners and in the sides 
middle). The illumination of fiducial marks will switch on pre 
cisely (up to milliseconds) in the middle of shutter operation. 
Such sincronisation guarantees reliable position of fiducial marks 
and by this way the equality of interior orientation elements. 
An additional (ninth) control mark is placed in the surface of 
moving camera frame and serves for control of F.M.C. operation and 
represents a transparent stroke in perpendicular to the direction 
of compensation movement. The stroke illumination is made from im 
pulse source with determined frequency. In the process of compen 
sating displacement, the image of stroke control mark file is 
printed on the air survey film. The distance between strokes Li is 
equal to Li = Vki:p, Vk - compensating displacement speed, p - de 
termined frequency. So by measuring distance Li on the film in the 
exposure moment and knowing p value, you can calculate the speed of 
compensation movement and its deviations. Another important feature 
of AFA-TK-10/18 is ratio W/H signal indicator which is integrated 
in the command board and allows to use air survey camera on air 
156