Archived posting to the Leica Users Group, 1998/03/05

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Subject: Re: [Leica] Off list; Noctilux effect; 35mm ASPH Ms
From: Jeff Moore <jbm@instinet.com>
Date: Thu, 05 Mar 1998 12:20:29 -0500

At  05 Mar 1998 05:40:41, Joe Berenbaum <joe-b@dircon.co.uk> wrote:

> At 21:48 04/03/98 -0500, you wrote:
> >At 04 Mar 1998 20:12:04 -0600, Eric Welch <ewelch@ponyexpress.net> wrote:
> >
> >> Ernesto. Now, just imagine what a 35 Summilux ASPH can do. <G>
> >
> >Create blocky, hard-edged out-of-focus areas?

> would I be right in thinking that the aspherical Leica 35mm lenses do
> render the out of focus areas substantially differently- have you observed
> such phenomena? I occasionally wonder about getting an aspherical 35 m lens
> and replacing my pre-aspherical 35 but I would consider such a change in
> the character of the oof areas most undesirable!

I wouldn't generalize so drastically.  I was echoing what others and I have 
observed with respect to the 35mm Summilux ASPH in particular, at some 
apertures.  I haven't seen anything so objectionable in the 35mm Summicron 
ASPH;  in fact, I can't really come up with anything optical* to dislike 
about the latter lens.  I bought one, and continue to be impressed with 
the "snappiness" of the images (a deliberately non-technical term to avoid 
saying something objectively incorrect).  (Oh, okay, I think I'm responding 
to contrast characteristics since most of the images I've looked at so far 
haven't been enlarged much.)  But the character of OOF areas doesn't rattle 
my nerves.  There may not be *quite* the perception of depth one has with 
the pre-ASPH Summicron at comparable apertures -- I get the impression that 
the price one pays in this design (is there a generality here?) for greater 
resolution at the precise surface of focus is a slight but noticeable increase 
in the rate at which resolution falls off as one moves away from that surface.  Can different designs have different depth-of-field characteristics for the 
same focal length and aperture?  Is it just that the lens is so dramatically 
`in-focus' that going out-of-focus seems that much more dramatic?  Erwin, 
help, I'm out of my depth here!

* Non-optical quibbles:

 - I agree with a previous poster that the new angled, pointy focus tab is 
   much less comfortable than the one on the pre-ASPH.

 - There's no excuse for having reduced the number of aperture blades.  
   Out-of-focus specular highlights appear noticeably less round.  This seems 
   like a simple and unacceptable example of cost-cutting gone awry.

The good mechanical things:

 - The aperture ring's enough more positive that it's a definite improvement.  
   The previous lens's ring would move if you looked at it funny.

 - They *finally* came up with a lens cap which goes over the shade.  Why did 
   they have to wait for a new lens to introduce it, though?