Re: [Leica] 50mm Optical Question

["Bud Cook" <budcook@ibm.net>]

Aren't the 90mm SummicronR, 135mm ElmaritR and 180mm ElmaritR modified
triplets (as is the Nikon 105 2.5)?   I've read somewhere that these lenses
were modified triplets and they look like Sonnars to me.
Of course I'm certainly no expert.
Bud Cook
- -----Original Message-----
From: Marc James Small <msmall@roanoke.infi.net>
To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us>
Date: Sunday, March 29, 1998 9:55 AM
Subject: Re: [Leica] 50mm Optical Question

>At 10:04 AM 3/29/98 -0500, Jim Bielecki wrote:
>>Does anyone know if Leitz (or Leica) have ever used the "Sonnar" optical
>>design for any of its 50mm lenses?  Or have they pretty much stuck with
the
>>"Tessar" design or the "Gauss" design?  Does the "Sonnar" type design have
a
>>"look" (I hesitate to say bokeh) that is distinct from the others?
>
>The short answer is a resounding "NO!".  The Sonnar formula is a rather
>severely modified triplet and is an exceedingly expensive lens to produce;
>some of the early Berek formulae are also modified triplets (such as the
>Hektor, Thambar, and the first Elmarit), but only distantly related to the
>Sonnar.
>
>Most of the later Leitz and Leica lenses have been modified unsymmetrical
>Double-Gauss derivations of one sort or the other.
>
>Zeiss has always aimed at the maximum performance on all optical axes, so
>their lenses avoid the distinctive flavour of early Leitz glass.
>
>Marc
>
>
>msmall@roanoke.infi.net  FAX:  +540/343-7315
>Cha robh bas fir gun ghras fir!
>
>