Elmar 3,5/50, Elmar 4/90, Summarit 1,5/50

[Erwin Puts <imxputs@knoware.nl>]

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. 
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 the corners it is quite weak. 
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!). 
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. 
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.
Greetings
Erwin Puts