Archived posting to the Leica Users Group, 1998/04/21
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On Wed, 22 Apr 1998, Dominique PELLISSIER wrote:
> >Your reasoning seems to be: some Leica lenses are bad because Leica has =
not
> >published the MTF graphs. All conclusions of Chasseurs d'Image are right
> >because no one contested them officially. In the same vein I could say:
> >Leica has never disputed my conclusions, so they must be correct and tru=
e.
> >Of course this kind of arguing cannot be proved nor disproved.
> >Erwin
> >
>=20
> Yes, I do think that some Leica lenses are optically overvalued.For
> instance in the M system : noctilux (oops !), summilux 50, summicron
> 90,tele-elmar.All these lenses have an old optical design while films hav=
e
> been hugely improved. But Leica is now on the road again with marvelous
> lenses : aspherical and apo.
> It is impossible for a firm to acknowledge directly that one of its produ=
ct
> is bad. For instance Leica says to me that "the tele-elmar 135 is not as
> good as the apo 180"(sic).You have to decode the message and it is quite
> clear.
> But it is still more impossible for a consumer (and you are and I am a
> consumer)to know if a product is good or not. That is the "information
> asymetry" :the firm knows the quality and you are in a veil of ignorance.
> So it is very important to have a "free" press as a counterpower. The pre=
ss
> can oppose a controversial position to the firm ideology (=3D"Our product=
s
> are the best in the world", and so on).=20
> That is why I don't understand your position as a consumer of Leica
> products. We ought to be critical.We ought to help the free press to
> develop a free speech.
> My opinion is that many "Leica fans" are alienated ( it is not an affront=
)
> in the sense given by the french psychiatrist Lacan : they adopt the spee=
ch
> of the others ("l'ali=E9nation, c'est le discours de l'Autre").
> I was also alienated in the past but now I am recovering.
Personally I have found published MTF charts like those published by Canon,
Hassleblad, Rodenstock, Scnider etc, can give one obvious messages about
which lenses are superior to which within a range. Admittedly they can onl=
y
really be compared within the same company ( i.e. Canon uses calculated MTF
charts ( I don't believe they allow for diffraction ) ), but from looking
at these charts one can get a good indication of the basic performance of
different lenses. For example :
( "better" in these evaluations means better contrast & resolution )
Hassleblad: The new CB80 is inferior optically to the CF80
The CF180 is better than the CF150 ( an older design ).
The CF350sa is vastly better than any of the previous >200mm
lenses ( except of course the CF250sa ).
Canon: The 50F1.0 is nowhere near a good as the F1.4 and F1.8 versio=
ns.
The 85F1.2 is much better than the 50F1.0 and is perhaps a be=
tter
choice for low light photography.
The old version of the 400f2.8 was clearly inferior to the ot=
her
telephoto prime lenses ( funny they recently came out with a
newer, much better version ).
The wide angle zooms are not too flash in the corners.
etc, etc.
BTW all of these observation have been verified by actual users of the lens=
es.
The other thing I do as a matter of routine now, is if I'm in any doubt abo=
ut
a new lens purchase, I go through a roll in the store ( or just outside ) o=
n
a tripod ( doing comparisons with an existing lens if necesary ). This is
just to make sure I don't get any nasty supprises.
Doing this testing has saved me from purchasing a Canon x2 converter, there=
is
a large and noticeable contrast loss. The x1.4 was much better and would h=
ave
been purchased instead ( I don't have cannon any more ).
Duncan
PS The Leica MTF charts clearly indicate that the tri-elmar is not opticall=
y to
the same standard as the primes. Its still fairly good, and if I were t=
o
be considering it, I would take out the tec pan and velvia and go down a=
nd
shoot a roll. Thats the final test as to whether its a suitable lens.
PPS I also read lens reviews, but one does need to understand the testing
proceedures to before one accepts the results.