🚀 go-pugleaf

"Chris" <Chris@swift.com.au> wrote:

> When the Epson ???? was released they quoted something like 800x1600 
> resolution the resolution in which the 1600 was double stepped to appear 
> like a 1600 scanner. But still the true resolution was still 800 dpi. 
> (There must be an explanation somewhere on the web how they come to these 
> figures.)
>
> I always only accept the smaller number as being the true optical 
> resolution.  Still 4800dpi is more than enough resolution for 35mm film.

The smaller number is still a funny number. Epson uses an "offset" CCD that 
consists of two half-resolution CCDs offset by 1/2 the pixel pitch. The 
result is that instead of the theoretically optimal point sample, it samples 
each pixel with an area much larger than the pixel size for the nominal 
resolution. The good news is that this should reduce grain aliasing, the bad 
news is that the resolution MTF is abysmally low above 1/2 the nominal 
resolution, so the appearance is a lot more like what you'd expect from a 
point sampling scanner with 1/2 (or less) the resolution.

The new Epson scanner appears to be playing the same game.

http://photo-i.co.uk/News/Feb06/Epson_V700_scanner.htm

(I almost always find that those guys get much better results from Epson 
scanners than anyone else does. Still, it looks pretty good.)

Also, the 6400 dpi is good through 4x5, so maybe 4x5 users with 64-bit PCs, 
tens of GB of DRAM, and a lot of time will be amuzed...

David J. Littleboy
Tokyo, Japan