On 09/06/2007 ppatton@bgnet.bgsu.edu wrote:
> 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?
The main issue with scanning at lower than 4000ppi is grain aliasing on
some materials (grain sizes near the Nyquist limit cause aliasing
artifacts which look like exaggerated and false-colour grain). This isn't
totally avoided in 4,000ppi+ scanners and Nikons have always seemed more
prone due to the semi-collimated LED lightsource. Nikon 2700ppi models
were especially prone, and most claims to see ISO100 grain in scans were
nothing more than visible grain aliasing.
I've only seen it twice with Polaroid 4000, in some overexposed Fuji200
col neg and in TMax3200. There is nothing you can usefully do with such
images.
I can't answer your optics question; all seem at least adequate. And
normalising the images via bicubic resampling means all bets are off
regarding a meaningful comparison - it's useful but it's not very kind to
image detail.
--
Regards
Tony Sleep
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