In the previous post I was observing that scanning slide film on Epson V750-M doesn't live up to the high expectations I had. Scanning some of the Xpan slides produced fairly low quality images that I wasn't satisfied with. So I started out by producing a more rigurous test between the Nikon Coolscan 5000 and the long awaited Epson V750-M.
To illustrate the difference between the Nikon Coolscan 5000 film scanner and the Epson V750-M flatbed scanner, I scanned a Schneider SMPTE RP-40 test slide (from Adorama) - click on image to see a larger size:
I zoomed on the center portion, which displays a series of lines, very small and hard to discern on a lightbox with a 10x loupe. Here is how the slide appears on the two scanners, with different settings.
Nikon Coolscan 5000, 4000dpi, 16 bit depth, color space grayscale, 1x multiple sample scanning:
Nikon Coolscan 5000, 4000dpi, 16 bit depth, color space grayscale, 4x multiple sample scanning:
Epson V750-M, 4000dpi, 16 bit depth, color space grayscale, mounted slide placed in mounted slide film holder:
Epson V750-M, 6400 dpi, sampled down to 4000dpi, 16 bit depth, color space grayscale, mounted slide placed in mounted slide film holder:
Epson V750-M, 6400 dpi, sampled down to 4000dpi, 16 bit depth, color space grayscale, mounted slide placed directly on the glass surface:
Epson V750-M, 4000dpi, 16 bit depth, color space grayscale, mounted slide placed in mounted slide holder raised 1mm:
As you can see from the images above, the Nikon scanner has a much better contrast, as well as much better resolution. The scanner has a builtin focusing mechanism, which by default is set to automatic, but one can adjust it manually in the software. When set to 4x, Coolscan's multisampling facility provides a much sharper image - this works by scanning the slide 4 times and combining the images. In practice the scanning time increases only slightly.
The Epson scanner's high resolution doesn't appear to make any difference in the quality of the image. Several people, including Fazal Majid in a comment on my previous post, suggested scanning with the mounted slide film raised approx 1mm. I did this experiment by placing the slide holder on few paper sheets stacked up to be 1mm in height, as measured with a digital caliper. As you can see from the picture above, this doesn't increase the quality of the picture. Update: Fazal pointed to Vincent Oliver's review and how the tab can be reversed to achieve the same height increase. The obtained scanned image is essentially the same as the one above.
In terms of quality there is no doubt in my mind the Coolscan is the clear winner.