Chuck Norcutt wrote:
> It doesn't matter how good the scanner. The dynamic range of Velvia is about
> 5 stops and the print less than that. The scanner probably can't match the
> dynamic range of the film (at least on one pass) but it's probably good
> enough for the range of the print which is probably less than 4.
>
Whoa! Wait a moment. I'm not sure I agree.
The range of brightness captured may be limited, but it's spread across
almost the whole range of transparency of the film, from almost
perfectly clear to almost perfectly opaque. What matters for scanning is
not only the range of the subject but that of the film.
In the case of slide film, the challenge is generally to capture the
whole dynamic range of the film. If the scanner can't do that in one
pass, the mechanical ability to make multiple, registered
passes/readings and software that can assemble them into a wider range
output are a big help. In my case, a recent test showed that 12 passes
made no difference in highlight or shadow detail in scanning an
Ektachrome 200 slide taken at night on a deck with tome bright local
lighting.
With CN and chromogenic B&W film, the challenge is to capture the subtle
graduations of tonality of a much greater subject range that have been
compressed into a smaller film density range. When digital measuring
devices became common, the problems of accuracy vs. resolution became
important. When the reading is 7.4, the natural tendency is to assume
the actual value being measured is 7.4. But if the accuracy of the
device is +- 0.2, the actual value is between 7.2 and 7.6.
With slide film, the much greater change in film density with subject
brightness means errors in scanning accuracy have less effect on the
tonal accuracy of the scanned output than for orange masked neg film.
I performed similar multiple vs. single pass scan tests on Portra negs.
Because of the lower DMax of the film, I didn't expect any significant
differences. Sure enough, no increased dynamic range. BUT - wait a
minute, resolution of fine, subtle detail increased noticeably! What's
that about?
I can speculate about extremely small mis-registration in the scan
passes capturing slightly different 'cuts' of the film grain. Perhaps
that and/or slight variations in brightness levels at the limits of
measuring accuracy combine to increase edge contrast?
Is this the case with other scanners? I don't know. My point, however,
is that the scanner does make a difference. The further point is that
extensive practice with scanner and software, working to learn their
subtleties can make a difference in the results one achieves.
I know nothing about Peter Lik other than what I've now seen from posts
about him. I do know enough from life experience to know that someone
who practices deeply and throughly with any limited set of tools is not
uncommonly able to achieve more with them than more casual or eclectic
persons who spreads their learning and use over a broader range of
things. I'm not, by the way advocating one approach over the other for
any individual.
It wouldn't surprise me at all to find that Lik has, by focusing on a
very limited tool set, work flow, learning how the variables of each
step work in great depth, for his WA landscapes, achieved results beyond
what more casual users of the same things can manage.
A couple of examples: Not all lenses of the same make and model give
identical results (Yes, AG, I agree.). Mike Hatems's compulsive tests of
multiple examples of MF WA lenses on FF Canons reinforce this point.
Someone focused on finding the best individual prime lens for a
particular camera and use may capture a better image in the camera than
someone using lots of different lenses and camera bodies.
In another area of workflow, I've found that NeatImage is generally a
great tool for both NR and some resharpening. I use it on image files
from a number of different sources, many different films scanned on a
couple of different scanners and files from three current and several
older digital cameras. The truth is that it is like sheer magic with
some image sources, ok with some and a struggle with others. If my
interest were to make the absolute best images with sources from a
single source, I might well try out all the NR and sharpening apps
available to find which one works best on my special files.
From lens through film through post through printer/paper through
display lighting, I believe intense work on a single path toward a
specific result will often defy common wisdom and experience about what
is possible.
This is true in many areas beyond photography.
Moose
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|