Figure 2 shows the experimental arrangement for a diaphragm in front of the lens, in 
which case the projected images are always circles of equal size. The arrangement for a 
between-the-lens diaphragm is shown in Figure 3. A practical example of an objective 
with the diaphragm between the lenses is given in Figure 4. The new wide angle ob 
jective Aviogon (Figure 5) by L. Bertele, shows a considerably smaller light loss. 
The old wide angle objective (Figure 6) shows a loss even greater than cos 4 a . 
Aviogon 
1,00 
1,00 
O 
O 
r.O 
ouO 9 
0,82 
0,66 
0,32 
o 
O 
O 
Aviogon 
1,22 
1,38 
1,52 
f/11 
0 
0 
0 
old wide 
angle lens 
0,90 
0,80 
0,55 
60 
90 
115mm 
31 9 
42 9 
50 9 
Fig. 4 The loss of light 
in the “Aviogon’' is 
nearly three times 
smaller than in earlier 
wide angle objectives 
(Example for 
f — 115 mm). 
Fig. 5 Section through wide angle objective “Aviogon \ 
Fig. 6 Section through wide angle objective of older construction.