Re: [Leica] Aspherical Summilux versions

[Erwin Puts <imxputs@knoware.nl>]

>As a photographer, Leica, among the many other reports I've read says the
>new one is better. In fact, there was a report by someone on Compuserve, I
>believe, who said that Leica and Zeiss both have decided that for the most
>part two aspherical surfaces in a lens introduce more problems than they
>correct.
>
These remarks are copied from my pen and numerous articles. The reason for
using asphericals is not the obvious one (correcting for spherical
abberation), that can be done with a 'normal' design too. But there are
more advantages as: being able to use less lens elements. BUT: less
elements mean less degrees of freedom for design and a more confined space
for optical solutions. As an aspeherical lens has a limited set of
correctional possibilities, the use of it introduces its own problems and
because we start with one lens element less the compensations are also
limited. Add a second aspherical and the problem is worse.
I discussed these matters at PhotoKina 1994 with the head of the Zeiss
optical design department, who had a booth opposite to the Leica stand. So
at 10:00 in the morning I got info from Zeiiss and went at 12:00 to the
Leica people referring to this info. They gave answers to defend their
solution and at 14:00 I discussed it again with Zeiss.What one would call
Kissinger type of pendel diplomacy. The resul tis well known: the new
Summilux! ;)
Erwin