[Leica] Summicron quality

["Erwin Puts" <imxputs@knoware.nl>]

When the first Summicron arrived on the market in 1954, it was a 7-element
lens with some novel properties, the air space in the split front lens being
the most obvious. With the help of new glasses, colour correction was very
good and so was resolution. Contrast was very low at the wider apertures and
you needed to stop down to f/4 to get really good quality. The Voigtlander
Ultron 2/50 of the same period used the same glasses from a British company
and was in the same legue. The second Summicron from 1957, the rigid one and
the DR which has the identical formula, was improved with higher overall
contrast at wider apertures, but at thet same time the Nikkor-H 2/50 for the
F and the Zeiss Planar 2/50 for the Contarex were very close in performance.
Leitz introduced the 6-element Summicron for the R in 1964 with an improved
design philosophy, clearly out distancing the M-brother and the competition.
Nikon countered with the new Nikkor-H 2/50 and Zeiss did nothing.
So whatever the relative performance of the 7-element Summicron in both
versions, there was even in its day strong and serious competition, and
after 1964 the design was made obsolete by Leitz themselves.
Anybody can see this for themselves, when reading the relevant reporting and
a correct description of the status of the Summicron 7-element would be:
"In 1954 Leitz introduced the Summicron 7-element lens, with visibly
improved imagery compared to the predecessor. It still is a low contrast
lens at the wider apertures, which introduces flare and reduces the
rendition of fine detail. At the medium apertures the improved colour
correction brings very fine and subtly graded images which exploited the
colour material of its days.Several companies were working in the same
direction, notably Nikon, Voigtlander and Zeiss, which gave the Leitz lens
stiff competition.
After 1964 the new Summicron for the R-body introduced a new level of
optical performance, that the M-version could not match. From now on the
Summicron-R defined the level of performance for a 2/50 standard lens. The
7-element lens was indeed replaced by a new M-version in 1969 that closely
follows the R-design. In absolute terms the older Summicron is not as good
as the newer version, but still delivers good imagery for many situations.
For best results the newer version should be recommended. The older version
may appeal to people who admire mechanical craftmanship, but in its optical
properties it is surpassed by newer designs."

We should never descbe a lens in terms of sharpness and/or resolution as
these concepts are subjective to the extreme (sharpness) and in most cases
irrelevant for image assessment (resolution).


Erwin