Film scanner sharpness

  • Thread starter Thread starter DavidTT
  • Start date Start date
D

DavidTT

My film scanner has auto focus only. Are there ways to evaluate whether
it is focusing accurately to produce a sharp scan? Thanks.
 
My film scanner has auto focus only. Are there ways to evaluate whether
it is focusing accurately to produce a sharp scan? Thanks.
Click to expand...

Scan an image of a sharp (high contrast) edge. How many pixels does it take
in the output, to transition from light to dark or vice versa? What are the
specs (optical ppi/dpi) of the scanner (it might help if you mention the
brand and model, I'm not clairvoyant). If it is capable enough, you might
see graininess, which should preferably be equally well resolved from center
to corner.

Bart
 
My film scanner has auto focus only. Are there ways to evaluate whether
it is focusing accurately to produce a sharp scan? Thanks.
Click to expand...


See a gallery of actual film scans from many
different models here:

http://www.terrapinphoto.com/jmdavis/

The standard here is 0.25" by 0.25" of film
surface at the scanner's best optical resolution.

No holds barred as to subject, film, camera,
lens, or technique. The title of the page is,
"How much detail from 0.25" by 0.25" of film"

It's not meant to be scientific, but it might help
you to see how your own scanner stacks up.

If you have a model I haven't listed or if you think
your scan is unusually sharp, I'll be happy
to post it.



rafe b.
http://www.terrapinphoto.com
 
Bart said:
Scan an image of a sharp (high contrast) edge. How many pixels does it take
in the output, to transition from light to dark or vice versa? What are the
specs (optical ppi/dpi) of the scanner (it might help if you mention the
brand and model, I'm not clairvoyant). If it is capable enough, you might
see graininess, which should preferably be equally well resolved from center
to corner.

Bart
Click to expand...

My Polaroid SprintScan 4000 has served me well for a couple of years
scanning Fuji Velvia and Provia and printing up to 13x19 on an Epson.
Now I'm considering upgrading to a Nikon 5000, Minolta 5400 or Canon
4000. I expect to get better scans from one of these based on the 16 bit
depth, higher dmax, and noise reduction by multipass or ICE/Fare. One
thing I'm wondering is whether I should expect better sharpness.

On the SS4000, I often scan very close to the slide mount edges for the
full frame, and never sharpen during scan. In PS, I'm able to sharpen
some scans very well but some with less success. Of course lots depend
on the original slides' sharpness and how well I sharpen in PS. But I
can't help but wonder what role SS4000 plays in focusing on the slides.
Some sharpening sw like PhotoKit recommends sharpening some during scan.
But my tests on the SS4000 don't seem to make a lot of difference.

I'll try your suggested experiment, and would appreciate comments on how
well the other scanners can focus.
 
Back
Top