Archived posting to the Leica Users Group, 1998/04/26

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Subject: [Leica] 21mm.
From: "Dr. Alberto Rodrguez-Robles" <arobles@coqui.net>
Date: Sun, 26 Apr 1998 22:45:08 -0700

Thanks Jim for your encouragement!

I used the 21mm Asph. with a junky Leica filter and without it.  I see
the same problems in both images.  With your lens make an image of a
white wall and see if edges and the corners have the same density as the
center.

Probably the lens is a bad one.  But what is happening in the quality
control stage at the factory?  How can you explained that the last four
lenses that I've tried have had the following defects: 
A- Summilux 50mm. 1.4 new, had a piece of scrap in between the elements
B- Summilux 75mm. 1.4 new, latest version, was unable to focus, it was
one feet off in the focusing scale.  Your subject was at a 6 feet
distance, measure with a measuring tape, compare the focus with a 50mm.
Summicron and a 35mm. Summilux and the Summilux 75mm. 1.4 gives you 7
feet when you focus through the range finder.
C- 21mm Asph. 2.8 that has vignnetting at all apertures and the focus is
poor on the edges and corners.  BTW the B&W enlargements up to 8x10 full
frame, image area 6x9, looks as if the photo were taken with a Nikon
point and shoot.  The lens was properly focus, by the range finder and
using the depth of field scale.  You cannot see the background in focus
even on some of the shoots the scale will tell you that everything from
3 feet into infinity will be in focus.

D- 24mm. Asph. 2.8 with vignetting.

I made the same shoots with the 28mm. third version and with the latest
version, 35mm. 1.4 Asph., 35mm f2 Asph. 35mm. last version, 50mm. coll.,
50mm. Summicron and 50mm. Summilux 1.4 and those images were sharp and
with proper focus corner to corner.

I used Kodak Elite slides, Fuji Neopan 1600 and Tri-X.  I developed the
B/W film in a JOBO and I made the B/W enlargements on a Beseler 45MXII
with Schneider 50mm lens and an Aristo V54 head.  The prints were made
on Ilford MG IV FB 8x10 paper and processed in Dektol 1:2 for 3 min..

The B&W negatives were read in a Riteway transmission densitometer and
they showed a light fall off of 1.5 stops from the center to the corners
and 2 stops toward the left upper corner.

I'm wandering about my luck when I'm buying Leica products.  I don't
know if they send the defective products to Latinamerica with the hope
that we don't have the same standards as the Germans for the optical
qualities or is just that the Germans don't have a strict quality
control as we use to have in our factories in America.

Anyway the quality control have been extremely poor from my experience
as a customer.

BTW I also made the same images with a Canon EOS 1N and a 24mm. 2.8 and
a 20-35 2.8 L lens and those images came out in sharp focus and without
light falloff nor vignetting.

Everybody on this list knows why we prefer Leica M cameras to shoot in
the steet and in an unobtrusive way.

Next week I'll send back the 21 and 24mm. Asph lenses and try the 21mm.
Biogon on a Contax G-2.

Well, Thanks to everybody that has been supportive and to those who has
challenge my trust in the Leica glasses.  I'll give it a chance and try
another 21 and 24 Asph. in the near future. 

Alberto


Jim Laurel wrote:
> 
> Alberto--
> My experience with the new 21mm asph has been very positive and I don't
> notice any of the problems you cite.  In fact, Karin and I have been
> pleasantly surprised at the performance of this lens.  Are you shooting with
> anything (like a junky filter) in front of the lens?  Maybe yours is
> defective?
> 
> --Jim Laurel
> Seattle, WA
>