🚀 go-pugleaf

On Wed, 01 Mar 2006 10:59:57 +0100, Ernst Dinkla
<NoEntry@pigment-print.com> wrote:


>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.


The snippets now showing at photo-i don't tell us very 
much, since we don't know the actual film areas involved 
in the hi-res samples.

Have you ever seen the lens in one of these film/
flatbed scanners?  Have you ever looked at the lens 
in an LS-8000/9000?

I really know very little about optics, and am 
seriously puzzled at the complexity of the Coolscan 
lens.  According to Nikon, it has 14 elements in 
six groups, and six of those 14 elements use ED glass.

Why?  I mean, this is probably more sophisticated 
than any *camera* lens I own.

In any case I can assure you that the lenses in the 
Epson 700/750 are nothing like this.  Also, in the 
Epson, there are probably several mirrors in the 
path between the film and the imaging lens.  Those 
extra reflections can't help the image quality.


rafe b
www.terrapinphoto.com