Re: [APML]: film resolution etc

[P3D John Ohrt <johrt@xxxxxxxxxxxxxxx>]

P3D Dr. George A. Themelis wrote:

> It seems to me that experienced photographers evaluate films by taking
> pictures and studying these pictures.  They do not evaluate films by
> looking at graphs or studying data supplied by the manufacturer.  No matter
> what the numbers say, the experienced photographer will make a choice by
> relying in his/hers general "feel" based on how the pictures look.

If you are producing "art", then the "feel" is of course most
important.  It is interesting though that films for technical
photography (eg. Tech Pan) are selected for one of the most demanding
areas of "feel", portrait photography for situations where the tone
(dynamic range) and high resolution can enhance the subject rather than
the more common use of softening filters to gloss over the details. 
When you have the perfect subject, the interests of artist photographers
and technical photographers are very similar.  Good technical
photographers are very aware of the work of Ansel Adams and others in
establishing the zone system.


> They
> shoot plenty of rolls before they commit themselves to any specific film.
> In the area of color photography, color reproduction appears to be much
> more important than "sharpness" or whatever, for the experienced
> photographer.  The fact that film A shows better "resolution" than film B
> usually means nothing to the experienced and practicing photographer.  If
> the choice was based only on "best definition", fast films would not be
> selling.

This soon may not be the case.  Once the tools of specialist technical
photographers are available commercially,  "colour correctness" is a
moot issue.  You can make it what ever you want.  Just check the current
(February) cover of Shutterbug for an extreme example of "color".  As
for resolution, I have the impression that a surreal element in a
photograph is currently "in".  There are many examples of art where
resolution is a key element in the "feel".

> 
> My point is that what you call "critical" information and you accuse film
> manufacturers for hiding, might not be critical at all for the experienced
> photographer, only the engineer with a curiocity or a passion for perfection.


We differ here.  My opinion is that if you are going to quote techincal
specifications they should relate in some meaning full manner to
functionality.  The "resolution" in lpm is a subjective evaluation at
one to two points of a continual spectrum.  MTR is an objective
description of performance across the whole spectrum.  I don't care that
"resolution" is an ISO spec., what is important is it is subjective, and
that means the data between manufacturers and film types is not
comparable.  Please note this is the most commonly quoted "spec" on
film.  Sheesh.  You and I may not be able to afford the test equipment
to generate an MTR, but film manufactures can, should, and some actually
do.  And MTR is totally objective and is comparable across manufacturers
and film type, and across the spectrum.  Which spec would you want
quoted?

 
> To get back to stereo photography, it is generally accepted that best viewing
> conditions are using a viewer.  A viewer magnifies the image only 5x.
> So, stereo photography is not as resolution-demanding as other forms of
> photography that use huge enlargements.

In technical photography, this just isn't "true".  I suspect that there
are areas of "artistic" practise where it isn't "true" either.

>  But the use of both eyes makes us
> more sensitive to (non-matching) grain patterns.

Agreed, but that only means that grain has a higher level of
significance compared to "normal" photography.  It doesn't mean you can
ignore resolution.

In summary, it is my opinion that "Joe Average" is on the threshold of
having available to him the "weapons" of high tech, tech photography. 
Afterall, it is just software.  They can be employed as deemed waranted
by the artistic community to achieve artistic effects.  Likewise, we are
on the verge of a different technology of stereo viewing wherein
alignment and resolution are easily improved beyond state of the art at
low cost.  After that, you can adjust the image in any manner you wish
to achieve the efects you what.

Please note that I am not dismissing "current" technology.  Ther are
certain effects easily achieved with it that are demanding in the
digital darkroom.  The converse is also true though!!!

What I concluded was that the current technical specifications are not
adequate to describe the film qualities and that those most prevasivily
quoted are subjective not objective.  I can live with my subjective
assessments, and so have to many other photographers, simply because of
cost.  There are good enough to assess better, worse, or no change in
many situations as long as all subjective assessments are performed by
the same person.  The film manufacturers don't have that "out" unless we
give it to them.  After all an objective mesurement is the always the
best basis for comparison.

Overall, I think we agree in most areas.

I was just remarking in one specific area, that the most widely used
spec is subjective, and that for purposes of comparison, may mean
nothing!  And you can never be sure what it means!  Nor is there any
magical formula to compare products in all aspects of use.

I just cross posted the article here in case anyone was interested. 
Interestingly, in astrophotography, the same divergence of view points
prevail.  The artistic photographers numerically are much larger than
technical photographers and tend to concentrate on the current "in"
area.  That's fine, that is freedom.  But they make pronouncements which
are taken as general "truths" by the newbies, which in fact aren't
"true" outside of the specialty of their current interest.  OTH, we can
quibble forever, which goes nowhere.

I was attempting to straddle the line by researching why the "artistic"
branch tended to believe specs in some areas and question them in
others.  What I found in this instance was that one of the specs they
"believed" in was in fact wholly subjective an no sound basis for
comparability.  If you really wanted to know, then you would have to
perform the best test you could manage with you performing all
subjective evaluations.

I have been save endless hours of testing based on well performed tests
by such people.  They can narrow the field down so that one or two
products or techniques are all you have to investigate.

I hope this was better explained the intent of my post.

Regards,
John

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John Ohrt,  Regina, SK, Canada
johrt@xxxxxxxxxxxxxxx
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