Not true at least with Polaroid. Each manufacturer has there own technique.
A brief overview of how we do it. We have a set of special targets and which
allow the scanner to see level 255 and a whole bunch of darkest levels. The
scans from the darker levels are analyzed for statistical differences in
density which factors in any CCD noise.
Remember it is NOT density as no film that I know gets above 3.6 - 3.8.
Using our technique I have tested a scanner that claims 3.6OD vs. the SS4000
claimed 3.4 and they came out identical. This is the same as reported in the
Mac World review of the SS4000
I will also say statistics can be manipulated to give most any answer the
sales weasels want. I have said many times on this forum I would not take
ANY manufacturer at face value particularly for OD.. As many of my customers
have done get a slide that has shadow detail and do the scan yourself or at
the very least have faith in an independent tester that knows what they are
doing. A novice can easily come to the wrong conclusion on some of these
tests.
David
-----Original Message-----
From: Rob Geraghty [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 09, 2001 6:18 PM
To: [EMAIL PROTECTED]
Subject: Dynamic range solved was Re: filmscanners: Sprintscan 120
now on B+H web site ...
Ed wrote:
>log10(2^13) = 3.913
>log10(2^14) = 4.214
Thanks, Ed! I remember Tony saying many times that there was no standard
way of calculating DR from scanners, but it looks like the manufacturers
have simply used the mathematics based on the bits from the A/D.
Rob
Rob Geraghty [EMAIL PROTECTED]
http://wordweb.com
