Re: Summicron 35mm f/2,0.

["captyng" <captyng@vtx.ch>]

>Bob Schwalberg, famous photo writer and former E.Leitz employee in the
>1960s told me about the "K" rule, named for Mr. Kisselbach (spelling?)
>of E. Leitz, Wetzlar. It is that, especially with wide-angle lenses,
>the smallest aperture you should use, before image quality goes down-
>hill is the divide-by-4 rule. You divide the focal length by 4. The
>result is the smallest aperture you should use. For a 35mm focal
>length, 35 divided by 4 gives you between f/8 and f/11. So f/11
>should be okay, but at f/16 you lose. I think it was Kisselbach...
>Now that Bob is gone I wish I had taped our conversations through
>the years. He didn't want me to do it, however. In 1966 he told me
>about an experimental M camera with a zoom-type finder system.
>Ed Meyers
>
>

Yeah, Theo Kisselbach.........  He had so many rules of thumb that when he
finished calculating his stuff the sun was down, the subject back home and
his wife in a profound crisis. He was a great technician though and a
teacher who knew his stuff very well.  During the war he was photographer
for a PK company, a propaganda company shooting for Goebbels' propaganda
ministerium and I saw pictures of him with a Leica IIIb in the cockpit of a
Dornier bomber over the Channel. He always was very much against the
development of a Leica reflex and as Ernst Leitz III used to listen to him,
he is one of the reasons that Leitz was late with the introduction of their
reflexcamera.

I have a copy of his Leica book "Das Leica Buch" edited in 1969 at home.
Although the pictorial material has aged, the technical side is still very
sound.

Gerard Captijn.