[Leica] Minolta Dual Scan III scanning times

[Martin Howard <mvhoward@mac.com>]

I ran the scan test on my Minolta Dual Scan III.  This is what I got.

System: PowerBook G4 800 MHz, 1024 MB RAM, OS X 10.2.6, USB 1.1, 
Photoshop 7.0.1, using the bundled Dual Scan Photoshop plug-in to scan. 
  No image correction was applied at the scan stage.

Index scan, 6 frames 35mm B&W film: 36.6s

Preview scan: 41.3s (with autofocus taking 36.5s)
Preview scan: 6.4s (with autofocus turned off)

Scan, 16bit, 8x overscan: 11m 42.9s
Scan, 16bit, 2x overscan:  3m 28.8s
Scan, 16bit no overscan:   1m 49.8s

Scan times were measured from clicking the "scan" button, to the 
instance that editing is possible again (i.e., including the extra time 
(10-15s) that the scanner needs to "think" after having completed the 
scanning of the frame).  I know from experience that exposure changes, 
histogram endpoints, and image cropping do not add significantly to the 
scan times, whereas changes in gamma or modification of the curve in 
the histogram add a lot of time.  I never do those in the scanner, only 
ever in Photoshop after the scan.

If you want to see the files that these scans produced, take a look at:

	http://homepage.mac.com/mvhoward/test/scantest.html

Differences appear minimal, if at all visible.  There appears to be a 
tiny bit of reduction in dust and scratches, but otherwise I can't make 
out any differences.  I purposely chose a difficult negative, thinking 
that the advantages of the overscan would be more apparent.

M.

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