Re: [Leica] Erwin's Leica Lens Compendium

[SthRosner@aol.com]

Good friend Tom:

Erwin's "Leica Lens Compendium" is indeed a remarkable and useful book, 
required reading for anyone having the remotest interest in Leicas. Still, I 
have to differ with the statement in your posting that the "latest version of 
the venerable 50/2 Summicron is undoubedly a better lens than its 
predecessors." 

Erwin would certainly agree that every lens is a compromise; there is no such 
thing as a perfect lens and cost must always be a factor, relating to a 
calculated guess as to a price the market will accept.

As I pointed out in Viewfinder magazine, Leitz designers of the current 50/2 
Summicron clearly opted for enhanced contrast at full aperture and were 
willing to accept somewhat reduced resolution. At some point, I hope to 
publish the reasons that, for me, the 50/2 Dual-range is a "better" lens 
while accepting that for others, the current formula may better suit their 
needs.

As to the philosophical point that Leica "never introduces a lens unless it 
is an improvement over a previous design," one perfectly acceptable purpose 
for redesigning a lens is to achieve equal or near-equal performance at a 
lower manufacturing cost, thereby creating a lower price for the customer or 
covering higher costs elsewhere in the process (labor etc.). Other purposes 
may be to take advantage of new manufacturing processes or to respond to a 
change in the perceived desires of the market.

As to the first, I corresponded with Wetzlar on precisely this issue, the 
differences in optical performance between the Dual-range and succeeding 50/2 
Summicron. Here is the verbatim (including the quotation marks) reply from 
Dr. Kurt Otto of Ernst Leitz Wetzlar GMBH under date of 24 January 1980: 
'Comparison of different lenses is always difficult. New lenses are in fact 
always "improvements" over older predecessors, but this will affect not only 
the image quality but in some cases mechanical properties (e.g. weight, size, 
number of air-glass surfaces, etc.). So it is not surprising to hear that 
some users will prefer older designs (with respect to image quality) and 
declare the new type "not (significantly) improved" compared to the older 
version.'

As to the latter (market preference), I quote verbatim from a most 
interesting letter I had from Geoffrey Crawley, then Editor of the British 
Journal of Photography, in September 1979. I had written, asking him about 
the comparative performance of the 50mm Summicrons. He answered: it is "my 
personal assessment that when steps are taken to make a lens more compact, 
there is usually some trade-off in quality. I would imagine that Leitz would 
be rather better than others at preserving performance, however, and it may 
be that they feel the purchaser of the later version [Summicron] is more 
likely to be using it for candid photography where the higher contrast can be 
more helpful than maximum resolution.....By the way, there is also the point 
that the Japanese go for high contrast and possibly Leitz feel they should 
align themselves with consumer preference in that respect."

The fact that you "still like the 50/2 DR better" accords with the preference 
of many Leica photographers, e.g. the recent posting of Mr. England who, 
admittedly, was comparing his DR with a Nikkor. But his description of the 
quality of prints produced by his DR is consistent with the experience of 
many.

Erwin has many times correctly pointed out that these differences are to a 
large extent matters of taste. It is therefore perilous to conclude that one 
lens is "better" than another unless one describes in detail the ways in 
which it is "better." That is what I shall try to do in a forthcoming article 
on the subject. 

Many thanks for your review and many, many thanks to Erwin for his laborious 
effort in producing such a valuable reference treatise.

Seth Rosner