Re: 35mm lenses compared?

["O.J. Anshus" <otto@cs.uit.no>]

> From: George Huczek <ghuczek@eagle.wbm.ca>
> Date: Sat, 17 May 1997 06:58:30 -0600
> Subject: 35mm lenses compared?
> 
>  Andrew Jordan wrote:

No, I am afraid I am the author of the following: 
 
> - - -The black Summicron had less vignetting than the "silver" Summicron.
> 
> Why?  Optically, aren't these two lenses essentially the same?  Is there a
> difference in the length of the lens protruding in front of the first
> element of these two lenses?

I don't know why. Perhaps it is the tight tolerances of Leica lenses
showing up? :-) 

> 
> - -GH

> From: Erwin Puts <imxputs@knoware.nl>
> Date: Sat, 17 May 97 17:05:11 +0100
> Subject: Re: 35mm lenses compared?(tech/optics)
>
<snip> 
> Well Andrew, this will be a long answer to a complicated problem.
<snip>
> At f/2.0 the performance of the ASPH is slightly better than at
> 1,4. In comparison the Summicron-M 35mm ( 7 element version) at f/2,0 is
> the equal of the f/2,0 performance of the ASPH. From then on both lenses
> are the same performance wise.
> So if the maximum aperture is not absolutely needed the current Summicron
> 35mm is certainly the equal of the ASPH at apertures from 2,0. Remember:

My latest version 35 aspherical is significantly better at f2 than at
f1.4 when I look at just the resolution. Using smaller aperatures does
not improve the resoluton for practical purposes. In practice, my
aspherical delivers top resolution already at f2, and has a higher
resolution at this aperature than the two Summicrons I tried (Well, at
least, the edges are sharper, and the small details easier to make out
when using the aspherical, all other parameters and factors that I could
control being the same). 

My aspherical has about the same amount of coma at f1.4 and f2 (close to
no coma at all). The two Summicrons I compared the aspherical with
clearly had coma at f2-f4, and gives the aspherical no contest at all.

> Erwin Puts

Otto