[filmscanners] film and scanning vs digital photography

["ppatton@bgnet.bgsu.edu" <ppatton@bgnet.bgsu.edu>]

---------Included Message----------
>Date: 9-Jun-2007 01:06:25 -0400
>From: <lotusm50@sprynet.com>
>Reply-To: <filmscanners@halftone.co.uk>
>To: <ppatton@bgnet.bgsu.edu>
>Subject: [filmscanners] Re: film and scanning vs digital photography
>
 (I think the
>objective consensus would settle on a 10mp equivalence with 35mm
film at
>100 ISO, and 8 mp at 400 ISO).
>
In my case, I got
>still further improvement in image information and detail moving
from
>4000 dpi to 5400 dpi (and these weren't even drum scans)  From
what I
>saw in my scans and from DSLR's, it was not until you got to 10
mp that
>image quality was really comparable (note, that I usually am
shooting at
>ISO 100).

A few weeks ago I tried an experiment.  I took an image that I
took in full sunlight with Provia 100 film with a Nikon N90s
camera and 70-300 mm Nikon zoom (of the World War II Memorial in
Washington DC).  I scanned it at 4000 dpi with my Polaroid
SprintScan 4000 scanner, giving a 5,375 x 3,546 pixel image.
When I enlarge the image I do see some irregularities which might
be film grain, but I can't tell for sure because I don't know
what film grain looks like.  I then used bicubic resampling to
reduce the image to the size of a Nikon D200 image ie. 3,872 x
2,592 pixels (10.2 megapixels- the equivalent of scanning at 2881
dpi).  I put the two images side by side on my dual monitors and
zoomed down to a fine image detail (a person standing near the
monument).  Although the pixels were clearly larger in the latter
image, it didn't seem to me that any image detail was missing.
This would seem to be consistent with the "objective consensus"
claim that 35 mm film at ISO 100 is equivalent to 10 mp, but it
would also suggest that there is no benefit to scanning film at
resolutions higher than about 3000 dpi.  This conflicts with
claims that it is beneficial to scan at 4000 dpi or higher
resolutions.  Am I likely seeing the limitations of the optics of
my scanner rather than of the information capacity of the film?
Anybody know how well the optics of the Polaroid SprintScan 4000
compares with those of Konica-Minolta or Nikon scanners?

___________________________________________________
Dr. Paul Patton
Life Sciences Building Rm 538A
work: (419)-372-3858
home: (419)-352-5523
Biology Department
Bowling Green State University
Bowling Green, Ohio 43403

"The most beautiful thing we can experience is
the mysterious.  It is the source of all true art
and science."
-Albert Einstein
___________________________________________________



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