Re: [Leica] scientific lens testing is ridiculous?

["David W. Almy" <dalmy@mindspring.com>]

All,

Erwin, as usual, is correct. However, in this case, Mike may be more
guilty of ready-fire-aim thinking than intellectual suicide. Mike, come
down off that ledge!

It also has been my experience over the years that lens test evaluations
often conflict to some degree. It is then our challenge to determine the
consensus view, combining the best science with the best user reports.
As a passionate user (who a couple of weeks ago saw one of my images
taken with an R8/70-180 at 2.8 enlarged to 16x24 FEET), I find the use
of lens tests to be an absolute imperative to my potential. 
Photography is permanently one part technical mastery and one part
aesthetic mastery. Therein lies the challenge.

Very glad Erwin is still in the saddle, 

David W. Almy
Annapolis

- ------------------------------

Erwin Puts wrote:
> 
> Mike wrote in part:
> >For the record, camera lenses are for taking pictures. The whole notion
> >of scientific performance evaluation of lenses is more than faintly
> >fatuous. It's _photography_. In photography, to paraphrase Ctein, if you
> >can't see the difference, it doesn't count. The way to evaluate
> >performance is on performance...literally, how the lens performs for you
> >when you use it.
> 
> This is in it itself a very old discussion topic. And I am most
> surprised this topic never seems to rise above the obviously easy
> dichotomy between artistic photography versus image performance.
> And as most people are  more versed in taking pictures than in
> evaluating lenses the majority of photographers (and some magazine
> editors) hold the position that the only correct way of evaluate a
> lens is to see how it performs in the personal type of picture taking
> and compared to one's own individual set of performance parameters.
> I never made any negative or pejorative remark about this view. I
> fully respect it. There are just several ways to analyze and evaluate
> an optical system. And none is more superior than the other. The user
> view is very good for the  person who needs this perspective. The
> scientific analysis is suited for people who want to know how a lens
> performs in optical terms. This scientific evaluation is done
> continuously by all lens manufacturers, so to say this act is "more
> than faintly fatuous" is a slight overstatement. Why can a person who
> feels inclined to the user perspective not be a bit tolerant to
> anyone who wishes to do a scientific test? I am a bit amazed that
> Mike, who in many postings and articles refers to his personal lens
> evaluations, denies the validity of a performance test of a lens
> according to measurable criteria.
> In my view there are several logical options here.
> Fact 1: we have lens tests done according to optical criteria and
> resulting in an aberration report and as example an MTF graph. These
> tests are useful for anyone who wants to know the optical quality of
> a lens.
> Fact 2: we have user reports of lenses, which report on many user
> related characteristics of a lens, related to practical demands.
> Opinion 1: both types of reports are valid and may in some ways
> complement each other. It is for any user to choose what type of
> report (s)he needs for choosing and using a lens.
> Opinion 2: I am aware of both types but the scientific one does not
> interest me. OR I am aware of both types but the user oriented  one
> does not interest me
> Opinion 3: only the user reports are useful and scientific lens
> testing is fatuous.
> In any normal discourse opinions one and two would be the most
> promising for a continuation of the discussion and may even reach a
> certain consensus.
> Opinion 3 is damaging to any rational discourse and so self defeating
> in the end. By negating and ridiculizing the work of thousands of
> optical designers all over the world, by denying that the performance
> of any lens might be studied according to objective criteria and
> measurable parameters and by denying that the scientific data may be
> of some importance for the quality of the photographic image, Mike
> commits intellectual suicide.
> 
> Erwin