Re: filmscanners: Scanner Focus

[Arthur Entlich <artistic@ampsc.com>]

Obviously, trying to use words to describe degrees of sharpness or
shadow noise is not very easily accomplished.

I suggest a few small samples or if you have a web site, placing some
there and linking your posting to them.

All scans are soft prior to unsharp masking, due to the nature of CCD
scanning.  Often the sharpening returns lost sharpness.

All CCD scanners also suffer from some shadow noise.  You can make it
worse by scanning with incorrect settings.  Certain scanners seem to
have less problems with this.  The Polaroids seem to have successfully
decreased  shadow noise in the 35mm and medium format scanners.  Nikon's
scanners are also pretty good in this area.

Art


HMSDOC@aol.com wrote:

 > I am an amateur photographer who is rather new at the whole scanning 
process
 > and have been lurking for a few weeks and appreciating the education.
 > Finally, made the jump and bought a Canon FS4000 which arrived 2 or 3 
days
 > ago.  I have 2 questions which I hope are not too basic for the group.
 >
 > The first has to do with focus.  Every review I have read has 
commented on
 > the sharpness of this scanner, and though I have read of 
dissatisfaction and
 > poor results with some other aspects of the scanner, I have never 
read of
 > anyone having problems with sharpness/focus.  So I was a bit 
surprised when,
 > to my eyes, the scans appear a bit soft.  I am starting out with 
sharp slides
 > or negatives with a tripod mounted Canon Elan 7 and good quality 
Canon prime
 > lenses and images that look sharp on a light table with a 4x loupe.  The
 > films are either Fuji Velvia or Provia for slides and Fuji NPS or NPC 
1660
 > for negatives. The auto focus is on, and the scans are at either 2000 or
 > 4000dpi.  With unsharp mask used to sharpen the image in my image 
editor the
 > situation improves significantly.  But how does one tell if there is a
 > problem with the scanner focusing mechanism?  If you take the scanner 
off
 > auto focus you would have to scan at each of lots of different 
possible focus
 > settings to compare to the original image.  I did try scanning at the 
two
 > extremes of the manual focus setting and the images appeared a bit 
worse than
 > on auto.  I guess my question here is how to know if the scanner is 
focusing
 > properly and am I confusing the concept of focus and sharpness?
 >
 > The second question has to do with background noise in dark areas.  I 
have
 > some slides with dark backgrounds from either flowers taken against 
black
 > backdrops or butterflies taken with a flash that illuminate the 
butterfly
 > well but leave the backgrounds dark.  When scanning and viewing in my 
image
 > editor I can see a moderate amount of shadow noise...but what is 
'good' or
 > 'normal'.  If I keep zooming in and blowing up the image it obviously 
becomes
 > more prominent, but at what point does it become poor performance or a
 > problem with the scanner.
 >
 > Thanks for any help.
 >
 > Howard
 > HMSDOC@aol.com
 >
 > .
 >
 >