Archived posting to the Leica Users Group, 1997/02/11

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Subject: Re: Elmar 3,5/50, Elmar 4/90, Summarit 1,5/50
From: D Khong <>
Date: Wed, 12 Feb 1997 06:15:43 +0800 (SGT)

Hi Erwin

Have you tested a 50mm Summitar f2? =20

Dan K.

At 10:54 AM 2/11/97 -0000, you wrote:
>A few days ago I could put some old lenses on the optical bench. Maybe some
of you might be interested in the results.
>The Elmar 3,5/50 (1932), uncoated. The sharpness in the center (a circle of
12mm diameter) is quite commendable, but with low contrast. The center
itself exhibits a resolution that is narly as good as that of the modern
lenses, but this can of course not be put on film beacause of the low
contrast. Outside this 12 mm circle the quality drops like the Niagara
Falls. Heavy astigmatism and field curvature and chromatic abberrations kill
every suggestion of quality. The astigmatism is such that when horizontal
lines are infocus the vertical ones are non-existent! (and the other way
around). This lens is well corrected for light rays which enter the lens
along the optical axis (the so called paraxial rays). The oblique rays
however play havoc with the quality. As it does till now. Optical progress
can be measured in  the corrections of these oblique rays.
>The Elmar 4/90 is much better (is has a smaller field to cover). The
quality circle now extends to 18mm and the fall-off is less pronounced. The
center quality however is not nearly as good as the corner quality of the
recent Elmarit-M 2.8/90, to put in perspective.=20
>The classical Elmar 2,8/50 (coated) still exhibits astigmatism but to a
lesser degree. Its quality circle is now =B1 16mm but outside this and in=
corners it is quite weak.=20
>As a sideline: the Minolta 2,8/45 (1948) in a Leica clone was slightly
worse than the Elmar 2,8/50 but  better than the Elmar 3,5/50 (overall image
quality but not in the very center).
>The Summarit 1,5/50 too exhibits strong astigmatism. Its circle of quality
is about 14mm. Then a gradual drop of quality can be seen. In the corners
however it is much better than the Elmar 3,5/50 and slightly lower in
quality than the Elmar 2,8/50. But we are talking of wide open aperture (1,5
versus 2,8/3,5!).=20
>The Summilux 1,4/50 (old version) is miles ahead of the Summarit in
suppression of astigmatism and coma. Its center sharpness in noticeably
higher, but in the extreme corners the Summarit is slightly better.=20
>The newest Elmar-M 2,8/50 is very well corrected and is almost up to
Summicron quality in the center (14mm circle). From then till the extreme
coners the quality is somewhat lower than the Summicron but the image
quality stays on a high level, there is no drop as with the older designs.
>Erwin Puts