155
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Direct position of the protective glass behind the objective al
lowed to take off the load caused by its fixing to the moving frame
and so this reduced significantly the assimetric part of distor
tion. Picture 3 shows the diagrams of medium range photogrammetrie
distortion of t.wo experimental samples of camera AFA-TK-10/18 and
this value does not exceed 4 yiikm.
Picture 3. The diagrams of photogramrnetrie distortion
of two o b j e c t. i x r e s A FA - T K - 10/ 18 .
The table shows the results of laboratoric tests of resolution
of the same experimental samples of objectives applying air survey
film T-4 2 and T-38. The first is of normal sensitivity near to 300
DIN and contrast index /=1,8 and resolution about 110 mnr 1 . The air
survey film T-42 has either triacetatic either "lavsan" base and
the thickness of 0,16 and 0,08 mm respectively. The air survey film
T-38 is of less light sensitivity (near to 75 DIN) and contrast in
dex /=2,1 and of higher resolution - 260 mm -1 . The last is made on
"lavsan" base and is 0,08 mm thick. The base of the air survey film
T-38 is of less deformation in comparison with air survey film
T-42 .
Up today air survey film T-38 practically was not used in mass
air survey operations caused by the fact that its low' light sensi
tivity brought to the necessity of long exposure time application
which originated inevitably an increase of forward motion image.
This fact repudiates high resolution of the pfotographhic film. Ap
plication of forward motion compensation opens new possibilities
for wide use of high resolution and low I ight sens itivitv ft i r sur
vey film and by this way to increase considerably the photoimage
resolution. The table proves this fact.
AFA-TK-10/18 camera has rotative shutter with independent petal
and damper drive which provide for minimum deformation of survey
interval.
