Archived posting to the Leica Users Group, 2003/05/16

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Subject: Re: [Leica] Vignetting of Summicron M 2/28mm ASPH
From: Henning Wulff <henningw@archiphoto.com>
Date: Fri, 16 May 2003 23:25:26 -0700
References: <03E63C98-8802-11D7-A816-0050E42E6E0B@shaw.ca> <001101c31c26$03b78680$0100a8c0@liyue>

At 11:40 AM +0800 5/17/03, Y. Li wrote:
>Thanks John. No, I had no filters, no hood on, but still vignetting. I just
>can't imagine a Leica lens at the price tag performs so badly.
>
>Y. Li

I don't have the 28/2 and haven't used it, but there is one basic 
fact with respect to lenses for rangefinder cameras and that is that 
the flange/film distance, and especially the distance from the rear 
element to the lens is much less than in lenses for SLR's. This leads 
to a number of design results; most good, and one bad.

The bad one is that light falloff in the corners is greater for the 
shorter focal length rangefinder lenses. A couple of tricks can be 
used to mitigate this, but the basic condition remains.

On the plus side, wideangle lenses for rangefinder cameras usually 
have _much_ better distortion control, and generally much higher 
performance with respect to most of the aberrations and are a lot 
smaller. You mentioned the Canon 28/2.8 previously. If you mean the 
EF lens, I have that one, and it is no match for any recent Leica 
wideangle lens (again, I don't have the 28/2 but I do have a number 
of others) except in eveness of illumination. If that is your main 
criteria for quality, then use SLRs. If you want flare-free, high 
contrast images with great resolution into the corners at all 
apertures, virtually no coma or astigmatism or colour errors and 
essentially no distortion, and wonderful build quality then use the 
Leica lens. No contest.

I have a number of wideangle lenses for Leica-M and for SLR's. All 
the SLR lenses are larger (sometimes huge), are more flare prone, 
have noticeable and sometimes severe and complex distortions, are 
noticeably less contrasty and less 'sharp', especially in the corners 
and are not always that cheap, either.

Stopping down a bit will certainly help with the light falloff; the 
fast SLR wideangles have severe light falloff wide open as well. 
Judge the relative light falloff at f/5.6 or so.

At 50mm, this becomes less of a factor and in the longer lenses a 
non-issue; in fact, the 90 AA has less light falloff than any other 
manufacturers lens in this general range that I know of.

As far as the price tag is concerned, you are getting amazing quality 
at f/2 and f/2.8. As I hear from various reports and users on this 
list, the 28/2 is the equal of the 35/1.4, and that lens has 
completely redefined what a very fast 35 can do. Yes, it has light 
falloff.

- -- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  /###\   mailto:henningw@archiphoto.com
  |[ ]|     http://www.archiphoto.com
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In reply to: Message from John Collier <jbcollier@shaw.ca> (Re: [Leica] Vignetting of Summicron M 2/28mm ASPH)
Message from "Y. Li" <liyue@netvigator.com> (Re: [Leica] Vignetting of Summicron M 2/28mm ASPH)