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Adjusting scanner focus

Anyone here ever attempted (or better yet, succeeded at) adjusting the focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old, still works, still as noisy as ever. It works, but it's certainly not a great scanner, and perhaps is doing the best it ever will do. But I'm not sure it's in focus. Having stripped down scrapped scanners, I know there's a focus adjustment, done at the factory and invariably set with some kind of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I suppose marking the current setting for return in case of problems, and trial and error could work.

The other annoying thing about the scanner is that it has to be "warmed up"; the first scan or two are always way too light and washed out. Is this typical of CCDs of this vintage? I remember seeing this same behavior with some low-res cameras my company used to use on a CD printing system we made, to take snapshots of CDs in the printer tray; our software took two or three shots, threw them away and then took one for real.

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Reply to
David Nebenzahl
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The 'warmup' is the CCFL. The problem gets worse as they age. Some change color before they fail, which screws up your white balance.

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Reply to
Michael A. Terrell

I would firstly try 3 test scans with a piece of paper, as normal, stuck under the doc glass and placed over a piece of glass over the doc glass, to see if there is a focussing difference

Reply to
N_Cook

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gn

I'm still trying to figure out why all of the scanners (four) I have ever bought have permanently broken down within 2 or 3 days after I buy them. Oy.

Ron

Reply to
Ron

On 1/3/2011 3:14 AM N_Cook spake thus:

Why bother doing that? Of course there'll be a focusing difference: the lens is wide-open, and therefore has a small depth of field, so moving the subject by the thickness of a piece of glass will make a visible difference.

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   To me, the *plonk...* reminds me of the old man at the public hearing
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Reply to
David Nebenzahl

Well, dooh: If one of the 'offset' images is much worse than the other, he'll know which way the focus has shifted with respect to the top surface of the scanner's glass. If there is no difference betwix the two, then the problem is probably not focus, but rather dust, etc.

Reply to
Allodoxaphobia

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