[Leica] imag quality old and new (never ending story)

[Erwin Puts <imxputs@knoware.nl>]

Ted asked for comment on this question:
>That being the case, does the aspherical configuration make for a better
>negative for the cost?  It does seem many LUG members stop there lenses
>down several stops and if the optical improvement is only appreciated wide
>open or near so, why are so many drooling over the aspherical glass?

Recent Leica lenses provide full aperture performance on a level the
previous generations reached stopped down at least two stops. The modern
lenses also get at their optimum much sooner than the older ones.  Many of
the new ones are at its optimum stopped down one stop. That is a big gain
in overall performance: at full aperture the quality the older generations
did not attain at 2.8 or 4.0 and at 2.0 or 2.8 better imagery than the
older ones at 5.6 to 8.0. Many modern lenses stopped down to 5.6 actually
drop a little  viz a viz peak performance. Do you see the improvements when
stopping down  to 5.6? Yes you do! The imagery in the field is  better and
the overall contrast is higher. If a lens has a higher degree of aberration
correction you will see it when stoping down, but of course the differences
are smaller than when comparing these lense at wider apertures. I do not
know why people drool over modern  Leica lenses? You do yourself and the
ambitions of Leice designers a disservice if you are not willing to expand
your vision, visual sensitivity and to upgrade your technique, even
handheld.
Walt wrote, at least in part, in his exemplary polite style:
>MOST of Erwin's admittedly superlative
>testing is PHOTOGRAPHICALLY useless.....there's NO photographic
>difference between ANY Leica lenses made in the last 30 years...
>bear with me.....what I mean is on REAL film (>ISO100, preferably
>400 for handheld work) at reasonable shutter speeds, HANDHELD,
>there is no visible difference. Period.  It's like the folks that
>can hear differences in line cords on audio amps...bullshit.
Walt's position is untenable. Exactly on real film (ISO 100) the modern
lense shine and outclass older designs. I have looked at my testresults to
see if I have instances of unreal film, but my D100, APX25, TechPan, D3200
and Kodachromes etc look real to me and on these filmtypes I can see the
vast improvements made since 1980.
But Walt and many others who defend their castle are jusified in doing what
they deem necessary. Fairy-tales are a healthy ingredient for many human
beings.

Alan commented:
>And also by the fact that the 80R and 75M have the same number of
>elements in the same number of groups (7/5). It seems logical to
>extrapolate from that that they are based on very similar designs, but I
>have no idea if this is the case or not. Did you compare the designs
>yourself ?

The number of elements and groups only indicate family resemblance.
Extrapolating this fact to indicate similar designs is a bridge too far.
Lens designs differ by curvatures of lens elements, distances between lens
elements and glass types. Even if the overall resemblance is close, these
paramaters really define the performance of a lens. And these differences
are not disclosed by most published lens diagrams.
Yes I compared the designs myself. I never base my conclusions on secondary
sources.


Erwin