ral consi- 
irting with 
The other 
r7 rg 
| for such 
J. 5). Any 
  
  
    
As | was entrusted with the problem of developing a wide angle lens of high resolving power 
| first came back to a glass sphere in the middle of the lens which | already had in mind when 
working on a wide angle reproduction lens. Extensive researches showed that this way led to 
a high resolving power and to an efficient magnification of the inlet pupil with growing angle 
of incidence towards the optical axis, just as for the above mentioned Steinheil lens. The so- 
called “Aviogon 90°” lens with a f:5.6 aperture has been many times described and success- 
fully used for several years (fig. 6). 
Having developed the Aviogon | once more took up my work on a reproduction lens and came 
to the f:5.6 Reprogon with a picture angle of 73° (fig. 7). In comparision with a camera lens the 
magnification lens has one more optical condition to fulfil: in the whole picture angle the inlet 
Reprogon f:5.6 (1955) 
pupil must be reproduced aberrationfree as outlet pupil, this in order to grant absolutely sharp 
and distorsionsfree pictures for the different continuously adjustable picture scales. For some 
lens types the insertion of a plane parallel plate between lens and film meets this condition. 
For the Reprogon this simple solution could not be applied, but the particular lens disposition 
enabled us to obtain the same result. 
In the Soviet Union Russinov took quite a different way in developing a super wide angle lens 
for small scale cartography. He had to solve the problem of letting a sufficient quantity of 
light through the lens for the picture corners. His solution is highly interesting. He encom- 
passed with two perfectly semi-spherical meniscusses two collecting internal elements the 
outer convex surfaces of which do not show close centres of curvature as this is the case for 
the Aviogon. Russinov therefore followed quite another principle as the above mentioned glass 
sphere. His lens has a maximum aperture of f:8; the reproduction power of this lens is un- 
known to me (fig. 8). Anyway this was the first survey lens having a greater brightness on the 
ri r2. r3 
  
Fig. 8 
Russar (1946) 
/ 
L1 12.13 L4 L5 L6 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
2 LE bros a 
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Ime 
  
  
  
  
  
   
    
   
    
    
    
    
   
  
    
    
   
  
  
   
   
    
  
   
  
  
  
adt os ét