[Leica] Viewfinder article

[TTAbrahams@aol.com]

	Erwin wrote:
>Did any one of you read my article about lensdesign in the most recent
>Viewfinder. Any comments on that.
>Thanks

Erwin, 
I read the article and it impressed me. Nice stuff! It will probably keep a
fair bit of the LUGgers and LHSA members up until late at night trying to
figure out what it is all about. It does explain some of the parameters that
Leica is up against when it comes to design and the fact that the computer
does a lot of the gruntwork, but it still takes a human to put the final touch
to a design. It is somewhat like alchemy - you have to try a lot of formulas
to find the one that turns lead into gold!
 Some years ago I talked to one of the optical guys at Midlands, he stated
that one of the limiting factors in the M-system is the small exit pupil of
the lenses, the bayonet mount limits the diameter of the rear element and this
puts constraints on the design of the optical path. Have you ever thought what
would be possible to do with a larger mount? There was talk of the M7 having a
SLR's sized mount and this would enable Leica to produce a more substantial
rear element and allowing them to make even faster lenses and cut down on the
aberrations inherit in the current lens path. There was even a joking remark
to the effect of a 35/1 Noctilux! That would get the LUG going. Well, I don't
think we can take another change of lens mount - some of us are still smarting
from the change to bayonet in 1954. I think I rather live with the current
limitations and try to use the lenses to their best performance limits
instead. Sometimes I think that our pre occupation with lens performance is
somewhat akin to using a Porsche 917-30 to commute to work in city traffic. It
is nice to know that you can hit 240 mph on the Mulsanne straight - but you
are still spending most of your life stuck behind a bus in city. 
 I have been promised a Heliar 15/4,5 and the 25/4 in the near future, looking
forward to try these out. Initial report on the Heliar are very promising.
The Ricoh 21/2,8 Asph is another lens that I am eagerly awaiting, it
supposedly tiny, almost the same size as the 28/2,8 Ricoh Asph. If that is the
case and the performance is up to par - that would be a good lens for travel. 
I am eagerly awaiting your next instalment, combining your article with Dick
Gilcrest's article on sharpness made the latest Viewfinder one of the most
interesting to read and one of the most challenging too!
All the best,
Tom A