Planar/Summicron 35

[Erwin Puts <imxputs@knoware.nl>]

Some people indicated their curiosity about Planar and Summicron
performance:

At full aperture the Planar-T shows very limited light falloff (slightly
less than theLeica Summicron ASPH), gives a high contrast image over
most of the  image-area, with the corners falling back a little.
Microcontrast is medium, giving softer edges on large objects and the
very fine details are not as crisply rendered as the Summicron ASPH.
Extremely fine details, that are within the recording capabilities of
the Summicron are lost in the Planar-T image.
At f/2,8 the microcontrast becomes higher and now the very fine details
are quite sharp and finely delineated. At f/4,0 the aforementioned
extremely fine detail is now visible in the Planar-T image. From f/11,0
the image quality, especially the contrast drops a little.
Flatness of field is is not as well corrected as with the Summicron
ASPH.
At a distance of ± 10metres the Planar-T images become generally softer
and the micro contrast is very low now. Very fine image details are
still visible, but the edges are soft and image lines are weak.
This performance I would not attribute to the lens. The excellent
performance at ± 3,5 metres would give the Planar-T very high marks. I
would suggest that we are finding the limits of the AF system in these
circumstances. And it gives credit to the position of Leica that a large
base mechanical rangefinder is necessary for very critical work.
In itself the Planar-T is a very competent lens, and from f/4,0 I would
rate it equal to the Summicron-M ASPH.
Study of the MTF graphs of both lenses corroborates the analysis given
above.
The two stops more in ultimate performance of the Summicron ASPH and the
greater accuracy of the M-rangefinder justify the M-6/ASPH35 combination

Erwin