Re: [Leica] Food for thought for Thanksgiving

[Thomas Pastorello <tmp@mailbox.syr.edu>]

Another clarification to Arturo and Tom D. :
   I think one does not have to argue whether the non-ASPH or ASPH lenses
are better.  They are simply different.  They will test differently on the
same type of test.  The ASPH's will test better on standard measures; the
non-ASPH's will test better on the edge spread width criterion.  If I may
add a subjective note, however, there is one test by which the traditional
pre-ASPH Leica M lenses will always test best:  the interoccular impact
test!   Tom P.

On Wed, 25 Nov 1998, Thomas Pastorello wrote:

> 
> 
> On Wed, 25 Nov 1998 AJSymi@aol.com wrote:
> 
> > Tom wrote:
> > 
> > snip "non-ASPH lenses, the 21-M 2.8, 35-M 1.4, 35-M 2.0, 50-M 1.0 and
> >  1.4, 75-M 1.4, 90-M 2.0 and 135-M 4.0, provide incredible three-dimensional
> > sculpting in a 2-dimensional image" snip
> > -----------------------------
> > Tom, are you saying that a lens can't have the above qualities and score well
> > on 2-dimensional test charts??
> > 
> > Arturo
> > 
> Arturo,
>    Osterloh said in the previously quoted book that magazines would
> publish lens test results in which Leitz lenses did not rank first.  He
> asked Leica users to not be upset, reminding them of their experiences
> with Leitz lenses and citing Leica's unique lens design philosophy (as of
> 1986).  It's become well known on this listserve that the Noctilux, for
> example, tests very poorly on standard measures. Yes, there's some
> incompatibility between the characteristics the traditional Leica lens
> user looks for and admires and standard testing procedures.
>    Dennis Laney in his book LEICA LENS PRACTICE (Hove, 1985) argues that
> an additional different type of testing is reuired for Leica lenses --one
> using the *edge spread width* criterion.  On P. 131 he says: *The Leitz
> Lens Testing Laboratory ... set out to find a method for measuring the
> image forming properties of a lens that could be directly related to the
> photographic image.  They started from the proposition that the subjects
> we photograph very rarely consist of grids of black and white lines on
> flat sheets of cards.*  His Chapter 9 explains valid test methods for the
> old (and gold?) Leica lenses.
>   P.S. I revised my e-mail because, in part, I left out in the list of
> lenses you snipped above what I think is the last great leica lens -- the
> latest 28-M 2.8.
>    Thanks for you comment.  I sure there are others who can answer your
> question better than I.   Tom P. 
> 
>