GV—96 PHOTOGRAMMETRIC ENGINEERING 
     
: 
i 
S 
S 
i 
Fic. 4e. Normal Kidney. 2 X. 
  
FrG. 4g. Band scar, cornea. 2 X. 
is such that no technical skill is necessary: focusing is accomplished by align- 
ment of two filament images; magnification, diaphragm, prism and light output, 
by scale; framing, by visual observation of light boundaries on the subject. 
To the professional photographer, the following data may be of interest: Film 
(color), daylight; picture size per frame of each stereo pair, 24 X30 mm. The 
lens is an 80-mm. f/45 Leitz Micro-summar. The shutter is incorporated in the 
mirror mechanism and has an effective speed of 1/50 second. The electronic 
flash unit utilizes a variable scaled power source in conjunction with a General 
Electric flash tube FT 218, and is capable of supplying a light ouput of 200 
joules. The lens diaphragm is kept at f/18. Adjustments can be made to use 
different effective inter-lens distances with a stereo-projector or stereo-viewer. 
Depth effect can also be kept constant or changed for exaggerated hyper- 
stereoscopic effects. 
The features of this camera are such as to require the minimum of attention 
from the photographer and allow him to devote most of his time to his subject.