Archived posting to the Leica Users Group, 2001/03/31

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Subject: [Leica] Erwin's Leica Lens Compendium
Date: Sat, 31 Mar 2001 23:46:06 EST

 I have had the opportunity to read Erwin's "Leica Lens Compendium" for a 
week now. I am a fast reader, a book a day is not unheard of when times 
allows it, but this is a book you have to read slowly. There is a wealth of 
information there. It is not "earthshaking" breaking news about sensational 
Leica optics, but there is a lot you can learn from it. I have used Leica 
lenses for over 40 years, most, if not all, of the M-lenses and LTM lenses at 
one time and another, but there was still stuff that I did not know. The 
first third of the book covers the History of Leica lenses and the criteria 
for designing lenses. It does make you appreciate the effort that goes into 
it, even with today's computer design. The amount of calculations required is 
mind boggling and in the "good old days" it was all done with pen and paper. 
It is quite interesting that some of these old lenses are still with us 
today. The original Elmar 50/3,5 even in its uncoated form is not a bad lens. 
The 50/2 Summar, much maligned but it can still give you a Bokeh that is 
unique. The surprise for me was the 50/2,5 Hektor. I have had several of 
these and always found it softer than I liked, but Erwin states  (and I 
believe him) that stopped down this lens was sharper than the Elmar 50/3,5. 
 There are excellent descriptions of the "faults" that makes a lens less than 
perfect. Erwin explains the aberrations, coma, color fringing  and all that 
stuff that we can blame less than perfect shots on. Heaven forbid that we as 
photographers would make any mistakes!
 The book covers lenses from 1925, the Elmax (low to very low contrast wide 
open, but improves when stooped down to 5,6) to the latest 28/2 Summicron 
Asph for the M. All of the R-lenses are covered too. 
 According to the book and also according to Leica's philosophy of lens 
design, they never introduce a lens unless it is an improvement over a 
previous design. This makes sense to me, why make something that is inferior 
or equal and go through the whole process of design and manufacturing just to 
announce something new. Now, we should also remember that what works for some 
of us, does not necessarily work for others. In most instances I agree with 
Erwin on his statement on Leica glass, but not on all of them. When and if 
you are testing optics, you use rigid tripods, perfect exposures slow film 
and controlled light when you can. This means that the judgement on a lens is 
under that situation. I shoot 99% hand held, Tri-X at 400 ASA, thus my 
criterias for a lens performance are different. My opinion is that the 21/2,8 
Asph is a sharper lens than the 21/3,4 Super Angulon, but I prefer the 21/3,4 
because the way it "models" light. The latest version of the venerable 50/2 
Summicron is undoubtedly a better lens than its predecessors, but I still 
like the 50/2 DR better, although I shoot with both lenses equally. The 35/2 
Asph is a spectacular lens, particularly compared to the earlier versions, 
when used wide-open, I still keep the old ones and one of my favourite 35's 
is an early 8 element Summicron from 1958. It does things with Tri-X that the 
newer lenses don't do.
 Oh, by the way, these are not new revelations to Erwin. I am lucky enough to 
count Erwin as a friend and we have had long discussions about these subjects 
 If you are really lucky, you might end up across the table from Erwin and 
get into this stuff. Trust me, you will learn things from that. I have talked 
to lens designers in Germany and Japan. In most cases I can't follow the 
discussion very long. They tend to go really esoteric after a couple of 
minutes or a couple of beers, whichever comes first. With Erwin you can drink 
red wine or beer and still understand him later in the evening!
 This said, I like the book and it is one of the first books on optics that I 
have read through, without skipping the boring stuff (there is very little of 
that). There are not that many MTF curves, which I like. MTF curves serves a 
purpose if you are comparing two similar lenses under controlled 
circumstances, but I have never knowingly taken lens A from the lens cabinet, 
because it has better MTF curve than lens B. Most of the time it is the lens 
closest to my hand when I open the door!
 So, ethically challenged as I am, I am shamelessly recommending the book to 
anyone who likes Leica and Leica lenses. Mainly because it is an unusually 
well written book and it does contain information that is interesting for the 
user, but also because Erwin deserves a lot of cudo's for writing it and he 
does know whereof he speaks! He has even consented to leave the odd mistake 
in the copy for people who likes nit-picking.
So get the book, get a good bottle of wine, beer or single malt. Sit down 
comfortably and read it whilst sipping the drink of your preference.
Tom A

Tom Abrahamsson
Vancouver, BC

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