Is that the design that some Biogons have to help lessen falloff?
Yes, the Biogon« design uses this phenomenon as well as most modern wide-angle lenses covering 90░ and above. The invention is to be credited to a Russian engineer, M.M. Roosinov just after the end of World War II.
The Zeiss Biogon« derives from the Wild Aviogon«... for the simple reason that both were designed by the same engineer, Dr. Ludwig Bertele. Both designs were patented in the early fifties.
Read more info by Marc James Small here : www.jborden.org/photo/Aviogon.html
The ideas cannot be better described than by reading Roosinov's US patent application.
US Patent 2,516,724
Patented July 25,1950
"Wide angle orthoscopic anastigmatic photographic objective"
Michael Michaelovitch Roosinov, Leningrad, Union of the Soviet Socialist Republics
Application August 23, 1946, Serial No. 692,477
Page one of the patent mentions this text which explains everything.
The diminution in the illumination of the image from the center
towards the edges of the field of view in conventional objectives is
in accord with Lambert's law cos^4 beta (the decrease is proportional to the fourth power of the cosine of one-half of the angle of
view), but in reality it is even greater due to the phenomenon of
'vignetting" -i.e. due to the sharp decrease of the area of the
entrance aperture of the objective towards the edge of the image, this
is an essential drawback of the existing objectives.
Thus, in all modern objectives the decrease in illumination according
to Lambert's law causes the illumination on the edge of the field of
view to be but 15-20 per cent of the illumination in the center, and
the decreasing the illumination attributed to vignetting causes the
illumination on the edge of the field to be but 30-35 per cent of the
illumination in the center; this reduces the total illumination on the
edge of the field, as was stated previously, to about only 5 per cent
of the illumination in the center of the field.
The urgent necessity for increasing the illumination at the edge of
the field of view brought about the use of the following arrangements;
(1) A star shaped rotating diaphragm built into the objective, serving
the purpose of increasing the exposure on the edge of the field of
view, and (2) the use of the Miethe compensator, however these devices
are not sufficiently satisfactory.
In a wide-angle objective embodying the present invention the
decrease in the illumination follows the law of cos^3 beta and this
makes possible the widening of the angle of view up to 120░ and more.
The outstanding feature of the present invention is an arrangement
of a super-wide-angle objective in which the phenomenon of
aberrational vignetting is utilized is such a manner that it increases the area of the entrance aperture towards the edge of the
field approximately by a factor of two; thus making possible a
broadening of the angle of view up to 120░ or more, with the resulting illumination on the edge of the field approximately equaling
10-12% of the illumination in the center of the field; thus, the
illumination of the edge of the field is twice that obtained with
conventional wide-angle objectives the angle of view of which covers
As you can seen, the fan-shaped mechanical compensator device is a pre-WW-II system. Early wide-angle lenses like the Goerz Hypergon were very difficult to use due to the cos^4 fall-off effect. Moreover the achievable image sharpness in the edges was extremely poor if judged by our modern standards. I have no idea of what a Miethe compensator is, but thin film deposition was not well mastered in the forties and fifties. Centre filters require a very precise control of the deposition of a thin absorbing film with decreasing thikness from the centre to the edges, following a precise law... something that has to comepensate for the cos^3 fall-of of our modern lenses.