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[OM] Re: Manual or Auto focus scan?

Subject: [OM] Re: Manual or Auto focus scan?
From: hiwayman@xxxxxxx (Walt Wayman)
Date: Sat, 29 May 2004 17:31:21 +0000
I am not as big a fan of Vuescan as many here, although I do use it with the 
Epson Perfection 3200, which I use for 120 and 4x5 scans.  I like it just 
barely enough better than Epson's software for this scanner to use it.  I tried 
Vuescan briefly with the Minolta 5400, but fairly soon went back to Minolta's 
software, which I find more useful, particularly, as Chris pointed out, for the 
manual focus feature.

As far as why Minolta's autofocus doesn't work as well as the manual focus, I 
can only make the wild guess that it tries to average out the entire slide or 
negative, which probably isn't all that flat.  With the manual focus, I pick a 
sharp-edged, high contrast area in the middle third of the image and focus on 
it.  It takes only a few seconds, and it makes me feel better.  Although I 
admit it has some advantages in some circumstances, I still take a dim view of 
any and all forms of autofocus anything.  I think I can always do better, and 
it's what I think that really matters, isn't it?

I promised a few days ago to explain what I did to my Minolta 5400 that I felt 
improved its performance somewhat, so here goes.  This scanner vibrates.  Mine 
sits on an old, very heavy, solid oak desk, and I could feel vibration in the 
desktop itself when the scanner was in use.  Being a veteran of years in the 
hi-fi wars and many a vibration search and destroy mission, I decided that the 
feedback from the vibrating desktop, while maybe not particularly detrimental, 
sure as hell wasn't likely to be beneficial either.

A bit of digging in a box of hi-fi odds and ends turned up just what I was 
looking for: a sheet of 1/4 in. thick Sorbothane.  The feet on the scanner, 
fore and aft, have thin little rubber pads on them, but that solid, hard 
plastic stand that sits amidscanner provides a direct mechanical connection 
between the scanner case and the desktop, providing an ideal path for vibration 
and vibration feedback.  So, I cut a couple of 3/4 in. x 2 in. strips to span 
the front and rear feet and a 4 in. circle to stick on the bottom of the stand. 
 Voila!  No more desktop vibration!

Post-Sorbothane, I scanned a couple of slides I had scanned pre-Sorbothane, and 
they seem just a bit sharper, with maybe a tad more detail.  It could be 
argued, of course, that this might be because of different scanner settings, or 
maybe that I've gotten better at focusing, or any number of variables, imagined 
and otherwise.  I suppose the only way to prove that this modification has made 
any real improvement would be to remove the Sorbothane, scan a slide, carefully 
replace the Sorbothane while preserving the settings, then scan the slide 
again, and repeat this procedure with at least eight or ten slides.

Let me say right here and now, no matter how much or how many inquiring minds 
may want to know, that ain't going to be happening.  I think it made a 
difference, and just like with the manual focusing, what I think is all that 
counts, isn't it?

Walt








> 
> Indeed Winsor, thanks for your reply.  It is a little strange to let 
> that sort of detail go to waste though.  And what of my question: if 
> the software can produce a little bar to tell you when you have a 
> better focus, why does the autofocus not use the same technique.
> 
> Chris
> 
> On 29 May 2004, at 13:00, Winsor Crosby wrote:
> 
> >
> > It would not be the first time that a third party wrote better software
> > than the manufacturer. For instance there are better printer drivers
> > than Epson's own and even Epson's Mac versions lack capabilities of the
> > Windows versions sometimes for years before they reach parity.
> >
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