35/1.4 ASPH, 75/1.4, coma & Leica after-sales support

[KEVIN BURKE <KBURKE@iterated.com>]

>From: Richard W. Hemingway

>I must plead quilty to the post about coma in one of the ASPH lenses.
>[...]

>Coma looks like triangle or butterfly shaped lights.
>[...]

>I was shocked to see the coma in the lights near the corners in the ASPH.

After reading Dick's experience, I tried a similar experiment with my 
75/1.4.
At f/1.4 the Christmas lights on the house across the street showed this 
75mm
to display a little coma in the corners.  I was a little discouraged since I 
had
read several descriptions of the lens that said things like "virtually no 
coma"
or "coma is not noticable in practice".  I guess the key words here are
"virtually" and "in practice".  I've seen similar Leica propaganda 
describing
the the 35/1.4 ASPH.  This makes me wonder if the average ASPH shows a
bit of coma and a few show none.  The results I observed with my 75/1.4
seemed somewhat better than what I've seen obtained with the 50/1.4.  Since
this is my first (and only) f/1.4 lens, I suppose it's a decent performance 
for
such a big piece of glass.

>[...]Since I got a good price for the lens I never sent it back to Leica
>- though I should not have sold the Leica gear and should have sent it back
>to Leica.

Leica may have responded favorably to the purchase of your new lens
but I have had no luck with them about imaging performance of my
lenses.  For instance, I had a third generation 28/2.8 M come unglued
after four years.  Leica USA sent it back the Germany where it was rebuilt
for a painful sum and about 3-4 months time.  When I started using it again
the results were different.  Originally, the resolution was very uniform 
across
the image.  The ultimate resolving power wasn't up to the seven element
35/2 but it was still very good.  The rebuilt unit ended up having blazingly
high resolution and contrast in the center with an annoying loss of 
resolution
and contrast toward the corners (also with some asymmetry around the
optical axis).  The effect was clearly noticable with Delta 400 enlarged to
8x12 inches.  I sent the lens back with before-and-after slides and 
negatives.
The lens took another vacation in Germany (2-3 months) for testing.  It came
back just as I had sent it.  It had been considered "in tolerance".  A phone
call to Roger Horne (president Leica USA at the time) bought me the
opportunity to purchase a new lens at their cost in trade for my old one
(after I paid for the rebuild).  I'm glad I didn't.  The fourth generation 
28/2.8
M came out a year later.

>Since I have sold all my Nikon gear and now have tow M6 bodies, 21/2.8;
>35/1.4 ASPH; 75/1.4; and 135/4.0. Interestingly, it is now a year since I
>tested the first ASPH and I tested the new one against the same string of
>lights (as well as other light sources) and did not find any coma.

I'm jealous. ;)  I want one of those!

 - Kevin
kburke@iterated.com