[Leica] 50mm rigid Summicron

[jbcollier at shaw.ca (John Collier)]

OK, now I am confused.

Are we talking about the second version Rigid and Dual Range versions?

If so, the optical formula is the same.

Are we talking about the first version Collapsible and the next  
version Rigid/DR?

If so, the optical formula id different

John Collier

On 27-Nov-06, at 4:58 PM, 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.