On 12/3/01 6:05 PM, EdHamrick@aol.com <EdHamrick@aol.com>, wrote:
>I understand what you (and others) are asking for. I'd probably
>implement this if someone could show (with actual scans)
>that specifying a focus point manually works better than what
>VueScan 7.2.11 already implements.
Here are two sample scans (one from VueScan, one from Nikon Scan) that
show the benefit of a manually selected focus point:
<>
Just another indictment of the limited DOF in the Nikon scanners, which
is why this feature is valuable. Note that this was just the first slide
I grabbed, and not one which is unusually bowed. I could probably come
up with more pathological samples.
There is a difference in contrast between the Nikon Scan and VueScan
images, and I did not try to equalize them. But I think you can still
see that the NS image is sharper, and that is because I was able to set
focus on the spot in the enlargement.
Doug Segar's earlier comment was important. If VueScan has a fixed focus
point, and that point happens to be in a featureless low-contrast area of
the image, you might get a bad result from the autofocus system. Maybe
you could get a better result by physically rotating the film, hoping
that the focus point is now over a more suitable part of the image. But
these Nikons need all the help they can get. When using Nikon Scan, I
set focus on the most important part of the image, or I look for a point
somewhere between the corners and the center, and also containing high
contrast detail. That's another reason why a grapical UI (click to set)
for focus point is preferable to x and y offsets entered as numbers.
--
Julian Vrieslander <mailto:julianv@mindspring.com>
