🚀 go-pugleaf

rafe b wrote:
> On Wed, 1 Mar 2006 11:51:27 +0900, "David J. Littleboy"
> <davidjl@gol.com> wrote:
> 
> 
>> 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...
> 
> 
> 
> I read at least one post on photo.net saying that the 
> V700 and V750 use the same CCD chip as the 4990.
> 
> So anyway -- from the dual lens trick, we'd still get 
> a 33% increase in linear resolution, if not MTF.

Rafe,

It is a 33% on both axis. The 9600 stepping rate over the 
length is in both SPI resolutions a heavy oversampling 
considering the well size. But the longer lens makes the 
scanned area (at one sample) covered by one well 33% smaller 
in both directions so the oversampling with the longer lens is 
reduced compared to the wider lens.

There's another concept change I think. Unlike the 2450 up to 
4990 models the lid isn't meant to be taken off for reflective 
scans of originals larger than A4. The DOF of the wider lens 
that covers the A4 scan bed no longer needs to have best focus 
at 1 mm above the glass for the film holders and still 
acceptable focus at the scan bed and the 2,5-3 mm higher rim 
around the scan bed. The longer lens takes care of the film 
holders and will have less DOF. The wider lens will focus on 
the scan bed and will have less DOF too. The scanning of 
originals larger than A4 is sacrificed for that with less 
sharpness.

The matrix CCD and the over-sampling still requires sharpening 
but less than with the lens system used on the older models.

I'm not surprised that photo-i gets so excited and I expect 
more than the 33% quality gain.

Ernst
                    --
           Ernst Dinkla


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