How to manual focus SM Pro with VS?

[Frank Kolwicz]

I've been using VueScan's auto focus for my Minolta Scan Multi Pro,
but now want to test it versus manual focussing, but I find no
information on how to do it. Do I have to do a new preview of the
image between manual changes of focus? Just dialing in different
numbers has no effect on the image that is already on the screen,
unlike other VS functions.

If a new preview is necessary, manual focussing will not be much help
as the SMPro is pretty slow at scanning for preview and that will make
it impossible to evaluate possibly a half dozen changes in manual
focus for any given image.

Frank

Personal replies to (e-mail address removed), if necessary, please.

 

[Ed Hamrick]

Do I have to do a new preview of the
image between manual changes of focus?
Yes.

If a new preview is necessary, manual focussing will not be much help
as the SMPro is pretty slow at scanning for preview and that will make
it impossible to evaluate possibly a half dozen changes in manual
focus for any given image.

Press the Save button after each change in focus.

Regards,
Ed Hamrick

 

[Bart van der Wolf]

I've been using VueScan's auto focus for my Minolta Scan Multi Pro,
but now want to test it versus manual focussing, but I find no
information on how to do it. Do I have to do a new preview of the
image between manual changes of focus?

The scanner must acquire a new, refocused image.

If a new preview is necessary, manual focussing will not be much help
as the SMPro is pretty slow at scanning for preview and that will make
it impossible to evaluate possibly a half dozen changes in manual
focus for any given image.

You can speed up that process by temporarily changing the Crop|Preview area
from "Default" to "Crop box". If you crop to a small region, only that small
region will be scanned (which is fast), and it will fill the Scan tab (makes
it easier to see what's going on).

Bart

 

[Bart van der Wolf]

Yes.

As I've mentioned before, it might be a useful future enhancement to provide
a graphical feedback for the focus contrast (or whatever measure you use).

In Autofocus mode, the scanner runs through the focus range. If a small
graph of the resulting evaluation is presented, then it becomes easier to
judge how critical (small steps) the focus accuracy is, or whether the range
of acceptable focus is broad (requiring bigger steps). It would also give a
sense of direction whether to in/decrease the focus value.

I often have to guess whether two focus samples are either on the oposite
sites of optimal focus, or the steps are too small to make a real
difference.

Some lateral thinking might even result in automatically taking several
samples across the crop area, and finding optimal depth of field focus for
curved films.

Bart