[Leica] Sufficient or maximum image quality?

[Erwin Puts <imxputs@knoware.nl>]

There is nice but not true story about the salesman of Rolls Royce,
answering a customer's question about the exact amount of horsepower of the
engine with the words: "enough, Sir"!
It might be argued and some posts do indicate this, that all Leica lenses
have 'enough' potential for image quality  for all but the most exacting
needs or for the farfetched demands of some testers.
In a sense I do agree. Many pictures of most every day scenes, including
night shots do have acceptable or pleasing quality for most viewers.
There seems to be a certain consensus that modern Leica lenses have in fact
many of the characteristics of older Leica generations, just  with a bit
more contrast. This is a  simplification and a misguided one. The overall
character of Leica lenses has changed  significantly since the designers at
Solms attacked the more viscious aberrations in a more effective way at
larger apertures and over a larger part of the image area.   Just looking
at resolution or overall contrast misses the point. I have elaborated on
these traits in many earlier posts and do not repeat them here.

Being involved at the moment in an extensive test of many modern
transparancy films in the ISO 100 to 200 class reminded me  anew of this
contrast between sufficient or maximum image quality. None of these films
will produce a bad image, all are fine grained (some more,some  less), none
gives correct colours (as measured with a computer assited colorimeter for
CIELab values of the MacBeth colour checker), that is most of them produce
sufficient imagery for most needs. Still some stand out for producing
maximum quality, that is matching the best image quality of the Leica
lenses. A good test is to take a close up of an object with extremely fine
textures and shadow details, three dimensional in nature with strong
specular highlights and some very sharply outlined colour patches. If you
do not find one object try to find several who combine these
characteristics. Then step back one  meter and take a picture of this
object again. Repeat this several steps back, every step one meter.
The trick is to look at the  various magnifications and to assess what
happens first: loss of image quality by the lens or the film. Then look at
the character of the image gradation. Then you get a feeling for the
potential of modern Leica lenses.

I am glad some posts raved about the new Apo-Telyt 135. It is a significant
step forward when compared to its predecessor in a test like the one
described above. I use this lens quite often myself. Testing all the films
mentioned above also again forced me to think about this fact: taken in
many situations (no not the twodimensional newspaper page!)  many pictures
looked good, but some looked much better in comparison. Of several hundreds
of  handheld shots a fair number exhibited the maximum quality possible.
Many however fell in the 80% category. Without comparison they would
suffice. With comparison they fail.
Important? I do not know if it matters to some Leica users. The new 24 and
the new 2/90 APO/ASPH and the new APO_Telyt 135 are not just a bit
improved. They change the way you look at your pictures and what you expect
from them. Of course the current 21, 28, the 35 versions, the 50 versions,
the 1.4/75 and 2.8/90 rate from excellent to outstanding if not superb. The
24, 90 and 135 referred to above are truly superb. Not improvable? I did
not say that. You never stop asking for more. Some of my pictures
(Kodachrome 25) with the new 135 were large format projected about 70 or 80
times. Standing in front of the screen (about  35cm I would say) I noted
that a very small detail in the outer zone of the image, that happened to
be very sharply delineated, exhibited a faint colour fringe. A bit of
chromatic aberration.  So no lens is perfect.


Erwin