Plustek OpticFilm 120 Pro
Silverfast scanner software.
Compare between a 48-bit scan of a 6x7 IT8 Color Slide with Single Exposure (top) and Multi Exposure (bottom).
To the right the Histogram info from PSE11.
The image had to be converted to 24-bit for this publishing.
With Multi Exposure the Scanner makes a second pass with longer exposures for every step.
According to the Silverfast theory this would enhance the dynamic range of the scanner because the darker regions (low pass through light) benefit from longer exposures.
But, honestly, I cannot see a real difference between the 2 scans !!
So this either means that the OF120 Pro is already good with a single scan pass
OR
that the Multi-Exposure feature just doesn't work at all.
When Multi-Exposure is selected the scanner does make a second pass at lower speed, so that part of it seems to work. But that is of course no guarantee that the ME software does its final conversion work correctly.
The very white area to the left of the greyscale is were there is no film between light source and sensor.
The very dark area to the right of the greyscale is were the film holder blocks the light completely.
Test done for this posting in the Rangefinder forum :
www.rangefinderforum.com/forums/showthread.php?p=2992503#...