Archived posting to the Leica Users Group, 2000/09/12

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Subject: Re: [Leica] Old S*****s vs. Old Summicrons and Summars
From: Dante A Stella <>
Date: Tue, 12 Sep 2000 22:37:56 -0400
References: <> <00d501c01d23$8b29b0c0$a9b360d1@durling>

[References to other LTM lenses have been redacted to prevent a riot.  But I am
happy that someone is showing interest in something more useful - like a
religious photographic war that was waged *forty* years ago!]


I'm sure Bob Schwalberg did, too, but the library with the best set I know of
(the Hatcher library at U of M) only goes back to about 1969.  Someone must
have done this.  It should have been about 1961, when I understand Leitz to
have overtaken Z***s in highspeed lenses.  I know that Erwin Puts did this test
at some point, because he references the Z***s transmission in one of his web
pages (but no data).


As a preliminary matter, I have not been able to test f/1.5 against a Summarit
50/1.5 - just 50/2 Summicrons verses the 50/1.5 Z***s and variants.  But I
think that the biggest difference is wide-open with the latter, so it is not as
unfair a comparison as you might think.

In reference to your question -- and this assumes we have a relatively flat
field in the frame, the S*****s, wide-open, tend to have a central zone of
focus that subtends about 1/3 of the frame.  From there the focus falls off,
arithmetically to the corners, which are quite soft.  I observed the sharpness
falloff also in the 40mm Sonnars in the R****i 35S and the XF35.

With the Summicrons (and generally with double-gauss lenses, even N****n),
there seems to be much more in the central area of sharpness (which extends
over - and I'm guessing since it's a round zone on a rectangular neg - about
70-80%), and where the sharpness does fall off, it does so very rapidly.  Both
lenses seem best at about f/8.

When we have a field with near and far objects, what this seems to be
translating into is much more aberration in the S****r in the out-of-focus
background, versus more controlled sharpness loss in the Summicron.  This means
better bokeh in the S****r, wide open (f/1.5-2).  That diminishes  a lot by
f/2.8 and completely, if I have recorded correctly, at about f/5.6 or 8 (which
are realistic shooting apertures).

The S****r also seems to separate highlights better than the Summicrons, which
does its magic in the shadows  I have observed this shadow separation in the 35
Summicron (4th gen) and the 50/2 (penultimate generation), as against Opton
S****r 50/1.5 and 2 variants (Soviet 50/1.5 and C***n 50/1.5).  I have not yet
had a chance to test this shadow-tone-separation phenomenon with an older
Summicron, say the first fixed one (but I know where to borrow one).  It is
interesting that Leitz lenses so strongly emphasize shadow detail, while the
S*****s seem to be fixated with highlights.  That may be an artifact of
double-gauss, so I will try to check that against some of my  N***n lenses.  I
suspect that Leica likes it that way.

A friend of mine who just finished testing a bunch of 50mm lenses that the
Z***s project a hotspot that is light-equivalent to f/0.9 in the very center at
f/1.5.  The Leica stuff is more true to scale, except for the Summar, which has
an actual transmission of f/3.5 wide open (or thereabouts).

Conclusion: Too close to tell.  The S*****s seem to have it for wide-open
portraiture, but for other purposes, it's a close call dependent more on
taste.  The Summicrons seem to be the better low-light lenses as far as holding
sharpness together across the frame wideopen and in the shadow detail
department.  I think I would take a Summicron into a cathedral and a S*****r
into a whitewashed Mediterranean village.

Maybe someone else can fill in parts I haven't gotten to yet.  This is not the
world's most scientific testing, but what you see in the prints and in hi-res
negative scans is a pretty good arbiter of what's going on with the sharpness


Mike Durling wrote:

> I bet Bob Schwalberg did.  I wonder if there are any archives of his work
> somewhere.  I suppose you could go to a library that has some Pop Photos
> from the '50s.  I know he wrote about both lenses in later years.
> Mike D

In reply to: Message from Dante A Stella <> ([Leica] Old Sonnars vs. Old Summicrons and Summars)
Message from "Mike Durling" <> (Re: [Leica] Old Sonnars vs. Old Summicrons and Summars)