Re: Minolta has discontinued its Medium format scanner

David J. Littleboy wrote: 
"One4All" <dwerner@xxxxxxxxxxx> wrote:

[snip]

To the best I can tell, the first tests of the 4870 showed it to be slightly worse than the 2900 ppi class dedicated film scanners, and nothing has changed since then.

http://www5e.biglobe.ne.jp/~longnose/scanner_test.html

For starters, the design of the Epsons (the offset CCD) precludes them from providing photographically significant image contrast above one half the nominal resolution.

Wait a moment, my 2400 dpi Epson scanner definitely provides significant resolution above 1200 dpi. The offset CCD design does make contrast go down fast quite a bit before Nyquist, but I don't think that's the problem with the 4800 dpi scanners from Epson, which, from tests I've lokoed at, don't give much resolution gain compared to *Epson 2400 dpi scanners*.

The extra resolution can help in preventing grain aliasing and allowing noise reduction to be more effective, but the MTF goes way down over 2400 ppi. People who like counting angels on heads of pins will claim that it can respond to patterns near its Nyquist frequency, but no one has seen that in real life from real images.

Well, depending on how you define "near", I'm sure my scanner can't provide any detail "near" Nyquist: it's flat zero after, dunno, 0.9*Nyquist, and very low after 0.8*Nyquist or so (I don't have the actual measurements available right now).

Still, 0.5*Nyquist is definitely visible *without* doing any processing on the scans. I guess up to 0.7-0.8*Nyquist should be quite easily recovered with some post-processing.

That doesn't mean they don't provide more than adequate scans from medium and large format for may users. Quite the contrary; for the price, they're wonderful. But they don't compete in either resolution or dynamic range with real film scanners.

This is also a point I'd like to quote: I've heard to many times the "flatbed scanners are useless for scanning film" statement. Flatbed scanners can do their work quite well for the average user, even though I wouldn't ever doubt that dedicated scanners do much better jobs.

by LjL
ljlbox@xxxxxxxxxx
.

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