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[OM] Re: Autofocus using Vuescan

Subject: [OM] Re: Autofocus using Vuescan
From: hiwayman@xxxxxxx (Walt Wayman)
Date: Sat, 14 Aug 2004 13:45:13 +0000
Oh, Moose, Moose, Moose...

The Minolta 5400 autofocuses just fine, thank you.  There have been a few 
occasions, however, when I have felt that focusing manually produced an ever so 
slightly sharper scan.  Could well be my imagination.

This whole subject came up probably because I have a natural distrust of 
allowing a machine of any sort to make a decision that I can make for myself.  
(Part of the reason, I'm sure, why I despise computers.)  If I can override the 
machine's judgment with my own, I'm pretty apt to do so, which is why I prefer 
to manually focus the scanner.  It comes down to doing something, not because 
it is really necessary, but JUST BECAUSE I CAN.

Besides, it takes less than 10 seconds to pick a high contrast area of 
importance and focus on it, far less time than I usually spend fiddling with 
that hystericalgram, or historicalgram, or whatever that bumpy, graphy-looking 
thing is, and moving the little slider hickies for all those other adjustments 
I'm allowed the privilege of making.

Hell, if, like long, long ago, they had put a lever on the steering column of 
the OM-4Runner that allowed me to advance and retard the ignition timing as I 
drive, I would use it regularly.  I hate the new TV because there's no fine 
tuning knob.  It may not need one, but I do.  My wife's Trailblazer has 
automatic headlights.  I hate when that happens.  I'm not so dumb I can't tell 
when it's dark.  The world today is full of these annoyances!

In conclusion, I am contrary and unlikely to get any better.  Maybe I'm a 
control freak.  Could that be why I use an old, out-dated camera system -- 
because it lets me do things my way? 

Walt


--
"Anything more than 500 yards from 
the car just isn't photogenic." -- 
Edward Weston


-------------- Original message from Moose : -------------- 

> I suppose I am being a PIA here. 
> 
> If I designed a film scanner that required manual focusing for best 
> results in any but the most extraordinary circumstances, I would feel 
> quite incompetent. 
> 
> - I would have control over optical design and thus depth of field and 
> field curvature. 
> 
> - I would know the characteristic shape of film in slide mounts of 
> various kinds and in the strip film holder I designed. 
> 
> - I could specify how film is placed in the scanner, so that the 
> emulsion side would be known. 
> 
> - It is technically pretty easy to measure the location of the face of 
> the film., either at the center, or sampled across the frame. 
> 
> Given that info, how in Heaven's name could I create a design that 
> didn't have proper focus across the whole frame? Sheer incompetence? 
> Bloodymindedness? 
> 
> People have been building film scanners for some time now. Most 
> maufacturers, certainly including Minolta, have been through several 
> design generations. This is not, as they say, rocket science, just 
> rather common engineering. 
> 
> My lowly Canoscan 2720 dpi scanner auto focuses perfectly every time as 
> far as I can see. Grain in the center is clear and and sharp as is grain 
> at the edges. 
> 
> As far as I can see, anybody who has to manually focus their new scanner 
> is in one of the following situations: 
> 
> - Has a defective scanner and should send it back for repair/replacement. 
> 
> - Has a defectively designed scanner and should return it for refund. I 
> find it hard to believe this is true of the Minolta 5400, but who knows. 
> 
> - Is operating the scanner incorrectly. 
> 
> - Has become convinced to worry about correcting something that isn't in 
> error in the first place. 
> 
> I know I would not stand for being charged good money for a scanner I 
> had to focus manually. Scanning is time intensive enough as it is, 
> without adding an unnecessary and time consuming task. Back it would go. 
> 
> A highly opinionated Moose 
> 
> Chris Barker wrote: 
> 
> >Dear All 
> > 
> >I have taken more interest in the AF capability of my Minolta 5400 
> >scanner since Walt muttered dark imprecations about its needing to be 
> >focused manually. I now sometimes take Walt's advice and focus 
> >manually with the Minolta software. However, I have also taken more 
> >interest in the focus cross in Vuescan's Preview window. Ed Hamrick 
> >has confirmed that it is the place where AF will take place (it was not 
> >clear to me from the instructions for Vuescan). 
> > 
> >Accordingly, my recent practice of dragging the focus cross to a 
> >contrasty part of the image *has* been of practical in use in improving 
> >the focus of my scans. I still use Minolta's software when Vuescan is 
> >defeated by the colour of one of my slides or negatives (pretty rare) 
> >and so will focus manually. 
> > 
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