Adjusting scanner focus
David Nebenzahl
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.
--
Comment on quaint Usenet customs, from Usenet:
To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.
Michael A. Terrell
David Nebenzahl wrote:
>
> 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.
The 'warmup' is the CCFL. The problem gets worse as they age. Some
change color before they fail, which screws up your white balance.
--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!
N_Cook
news:4d21a1b8$0$30399$8226...@news.adtechcomputers.com...
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
Ron
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
David Nebenzahl
> David Nebenzahl <nob...@but.us.chickens> wrote in message
> news:4d21a1b8$0$30399$8226...@news.adtechcomputers.com...
>
>> 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.
>
> 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
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.
Allodoxaphobia
> On 1/3/2011 3:14 AM N_Cook spake thus:
>> David Nebenzahl <nob...@but.us.chickens> wrote
>>
>>> 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.
>>
>> 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
>
> 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.
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.