TOPAR LENS 1:4/f — 210 mm for 18 X 18 cm AERIAL CAMERAS 
by Dr. RoBerT RICHTER, Zeiss-Opton, Oberkochen, Germany. 
Zeiss’ first new creation after the war in the field of photogrammetric survey 
objectives has now reached a stage of completion that we may venture a forecast 
on the results that can be obtained with this objective. 
This lens is the T'opar 1:4/f — 210 mm for a picture size of 180 X 180 mm. 
The objective has been developed by the author in collaboration with Mr. F. Koch 
on the principles of the Topogon lens in an effort to replace the pre-war objectives 
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50: 
40 + 
Linien N 
© 
i 
Aw N 2 
o Pro mm 
  
1 1 ! 1 1 1 1 1 l 1 1 i 
0 Bidhthe 30 4 50 60 70 80 90 100 10 mm 
bee 1 1 1 1 1 J 
0° Bildwinkel 10° 45° 20° 25° 30° 
Fig. 1 
Resolving power of Topar 1: 4/f = 210 mm for grid test at full aperture, 
in lines per mm. 
K = 1.6 Perulith Pan without filter 
K = 1.6 Aviphot Pan 30° Sch. Filter D 
K = 0.25 Perulith Pan without filter 
K = 0.25 Aviphot Pan 30° Sch. Filter D 
SAWN = 
by a better one. The results are up to our expectations; it has been possible to 
reduce all image errors discussed in the theory of geometrical optics to two fifths 
of the former values. In particular, this applies to spherical aberration, curvature 
of the image field, and distortion. The decisive test at the photographic laboratory 
of Zeiss-Opton was performed by Dr. H. Sauer. 
It is a well-known fact that we have always declined to give data on the 
resolving power in catalogues which are destined for a larger public. In this 
matter, we are in full agreement with opinions which have recently been voiced 
in the United States. As a matter of fact, we have used the measurements of the 
resolving power for our own information, where all chemical and physical factors 
bearing on the accuracy of the measurements as well as the dependability of the 
laboratory personnel are known. However, we omit on general principle to 
publish these values, for it may always happen that other data obtained under 
different conditions may undeservedly be given a higher or lower rating. 
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