[Leica] 50mm rigid Summicron

[durling at cox.net (Mike Durling)]

Are any of Bob Schwalberg's writings published anywhere or online?  I 
was very fond of his later work, and would love to find some of his 
earlier writings.

Mike D

Marc James Small wrote:
> At 06:11 PM 11/27/2006, Phil Swango wrote:
>  >Marc Small wrote:
>  >> I believe that the Rigid 2/5cm Summicron is identical
>  >>optically to the DR/NF version of that lens, the only difference 
> being in
>  >>the lens mount, but I have never researched this and that could be a 
> third
>  >>design based on a common pattern.
>  >
>  >That's what Erwin Puts says too.  I don't know if he's a reliable 
> source or
>  >not.  I've had both and couldn't see any difference.
> 
> Phil
> 
> Measure them.  That is the difference.  The Rigid has a longer front 
> element to rear element distance, which requires a redesign.  I did a 
> LOT of research about this 12 years or so ago, back in my days on 
> Hummingbird Lane, but my notes are not with me at the moment, and my 
> leaky memory nly recalls that there is definitely a redesign of the 
> collapsible to rigid design and, probably, a further redesign to the NF 
> version.  Leitz was being slammed hard at the time over its lens designs 
> which made them most unwilling to discuss these redesigns or those of 
> the 1.4/50 Summilux, not admitted until 1966, some four years after that 
> revised lens appeared.
> 
> Mandler seems to have been the brains behind the redesign of the 
> collapsible Summicron to the rigid lens.  Wright and Glanfield were the 
> first to note the discrepancy but the man who made it obvious was the 
> late and VERY lamented Bob Schwalberg.
> 
> I am embarrassed to be caught, once again, without my notes at hand, but 
> I will confidently state that the rigid Summicron has a greater depth 
> than does the collapsible lens, and that the collapsbile Summicron 
> design was clearly tweaked by Mandler to produce the rigid Summicron 
> design which was, most likely, further tweaked for the NF version of the 
> rigid M BM lens.
> 
> I do recognize that Leitz has maintained that these lenses were 
> identical in design.  However, operating from memory, there are 
> differences in the patents for these lenses and, I vaguely recall, an 
> internal Leitz memo discussing this surfaced some years back.
> 
> I had promised the late Roy Moss an article on this during his tenure as 
> VIEWFINDER editor but it got set aside in the course of my work on my 
> Zeiss book and I just never got back to it, though I did get a prompting 
> e-mail on this from Roy from around 1995.
> 
> Marc
> 
> 
> msmall@aya.yale.edu
> Cha robh b?s fir gun ghr?s fir!
> 
> 
> 
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