focus and color-misregistration with Powerlook 3000

[don.williams]

Gentlemen,

I would just love to use the Silverfast AI driver we purchased for our Powerlook 3000 but have found that unlike your drivers for other devices it has no manual focus option. Can you confirm that this is true for the Powerlook 3000? I believe this is a real problem at dpi's greater than 1200 because
I see a dramatic real resolution difference (using resolution bar targets) when capturing images with your driver versus the Magicscan driver at dpi's greater than 1200. BTW, I am
using sanctioned ISO methods of ISO 16067-1
to determine this real resolution using
MTF techniques,

Also several months ago I asked M. Leschke
of your U.S operation about a color misregistration artifact we detected at the 300 dpi scanning range. It manifests itself as a green/megenta cast across horizontal edges of the text.

I did a little more research and found that
the color misregistration using the Silverfast disappeared in the transition between 381-382 dpi. ( I didn't check where it disappeared below 300 dpi. I ran the same experiment several times and have found the color-misregistration does NOT occur with the Magicscan driver. At that time
I sent a sample set of images for your
review. I've heard nothing.

If it helps, We're running Windows NT OS.
Can you please help on these issues? I would like to get closure on these before my scanner critique is published.

[LSI_Support]

On 2002-07-31 17:48, don.williams wrote:
Gentlemen,

I would just love to use the SilverFast AI driver we purchased for our Powerlook 3000 but have found that unlike your drivers for other devices it has no manual focus option. Can you confirm that this is true for the Powerlook 3000?

Yes, this is true, the hardware-focus control for this scanner is limited to four possible focus possitions.

I believe this is a real problem at dpi's greater than 1200 because
I see a dramatic real resolution difference (using resolution bar targets) when capturing images with your driver versus the Magicscan driver at dpi's greater than 1200. BTW, I am
using sanctioned ISO methods of ISO 16067-1
to determine this real resolution using
MTF techniques,

Explanation of the new autofocus-options in Umax Powerlook 3000
--- this new focus button has four possible setting:
0.0 with no indication (minimum distance to scan material)
0.0 with the "A" letter indicated.
0.6 with no indication (maximum distance to scan material)
0.6 with the "A" letter indicated.
where the 0.6 focus is meant for framed transparency slides, and the 0.0
focus is for plain transparency material (unframed).
NOTE: both focus values do not describe fixed distances when the
A-letter is shown.
The A-letter indicates that the scanner "finds" automatically the
optimum focus distance for the current scan-material, where "0.0, A"
sets the optical focus somewhere between 0.0 - 0.3mm distance and "0.6,
A" sets the focus somewhere between 0.3 - 0.6 mm.

Also several months ago I asked M. Leschke
of your U.S operation about a color misregistration artifact we detected at the 300 dpi scanning range. It manifests itself as a green/megenta cast across horizontal edges of the text.

I did a little more research and found that
the color misregistration using the SilverFast disappeared in the transition between 381-382 dpi. ( I didn't check where it disappeared below 300 dpi. I ran the same experiment several times and have found the color-misregistration does NOT occur with the Magicscan driver. At that time
I sent a sample set of images for your
review. I've heard nothing.

Well, I only got the one image with numbers on it (possibly demonstrating sharpness) If you haven't had any other response so far, please contact support@silverfast.de.

[petervogel]

hello,

I am a Linoscan 1800 user, which as far as I am informed is the same hardware as your scanner.
Since Linocolor Elite will not be ported for OS X any longer I have asked Lasersoft if they would support this scanner and I got a yes.
So I downloaded a demo of Silverfast 6.x for my Scanner under OS 9.x and have made some comparison tests with Linocolor Elite.
Well, I have the same problems that you descibe. Needless to say, these scans are worthless, because they are totally out of focus, no matter how I adjust unsharp mask. The Linocolor Elite scan looks crisp and sharp even though I haven't applied any unsharp masking and the colors in standard setup are also far superior.
Right now Silverfast is not an option at all. Just to let you know, that you are not alone. I wonder how they can even sell this software to customers of these higher end scanners?

cheers
peter