There's nothing wrong - they only show the inner part of the chart scanned with the Plustek:
It just shows, that Plustek's infernal resolution is only impressive on paper - the quality of the scanner lens must be low. The contrast is poor, and DR is very small. I also wouldn't expect that merging different exposures would make things better. You get what you pay for.
I see what you mean. I didn't think the difference between 3500 dpi and 3900 dpi would be that noticeable. Contrast is something that's adjustable in the scanner's software, or in Photoshop. The histograms of these test targets look so different, I wonder if ScanDig simply used the scanner companies' own software in default mode when they scanned this target. SilverFast's Ai Studio with calibration target is expensive software. Nikon Scan that ships with the 5000ED would be better than Plustek's own software but probably not as good as SilverFast 6.5 Ai Studio with multiple exposure.
I've downloaded the rez charts for the Nikon 5000, Minolta 5400 II, Plustek 7500 and Epson V700 flatbed, enlarged them to get a clearer idea of what's going on, and adjusted the contrast. As you can see, the resolution of the KM 5400 II is the highest, as described by ScanDig at 4200 dpi. Both the Plustek and the Epson V700 show visible CA, whereas the Nikon and Minolta are free of CA, but you'll notice that both the Minolta and Plustek scans seem to have blown highlights. The whites are whiter and the marks and scratches on the test target have almost completely disappeared in the case of the Plustek scan.
The Dmax of the 5400 II is supposed to be impressive 4.2 (from memory) so there's no reason why a scan with proper adjustments would not pick up the details of the scratches and marks in the highlights of the test target, if appropriate software adjustments were made before scanning.
The other problem I believe, is that Nikon no longer make film scanners. Is this true? If it's a choice between the Plustek 7500i and the Epson V700, I'd definitely go for the Plustek.
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