Slides scan out of focus

  • Thread starter Thread starter Ercole
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Ercole

Hello, I've a Canon 3200F flatbed scanner with film/slides adapter.
When I scan negative film the quality is good enough (is a 1200 x 2400
scanner), but when I scan slides mounted with frames the results are
most of the times out of focus. Is a common problem with flatbed
scanner?
Any suggestion for resolve the problem?
Thanks
Ercole
 
Ercole said:
Hello, I've a Canon 3200F flatbed scanner with film/slides adapter.
When I scan negative film the quality is good enough (is a 1200 x 2400
scanner), but when I scan slides mounted with frames the results are
most of the times out of focus. Is a common problem with flatbed
scanner?
Any suggestion for resolve the problem?
Thanks
Ercole
Click to expand...

Sometimes it is the frame, particularly the plastic type (popular with
company A/V departments) that pop together if the frame is not tightly
closed, is warped, or is simply cheap. I have also had problems with
old glass slides where the slide has shifted in the frame so that the
metal foil on the glass is exposed slightly, changing the distance from
the screen. These I remove and scan directly on the scanner. Adapters
in general are so-so for slides in any event - good enough for
Powerpoint, often not good enough for quality archiving. Also, slides
can be dirty or filmed with residue which can show up as a foggy scanned
image that appears like it is a focus issue. Additionally, the scan
resolution you are using might provide a good 1:1 scan, but in an
expanded view on the computer display is showing the limits of
resolution, not really out of focus at all.

Q
 
Yes, it is a common problem. There is (usually) no focus adjustment on
flatbed scanners, and in my experience they are not well focussed. I
believe they count on the DOF being great enough to hopefully include the
plane of the glass surface in the focus range, but most won't actually
achieve more than 1000 dpi or so.

I have an Epson 1640SU with a slide adapter, and it will resolve about
1000-1200 lpi at high contrast, even when scanning at 2400 dpi.

Don
 
Ercole Carpanettoin article
(e-mail address removed), Ercole
Carpanetto at (e-mail address removed) wrote on 1/4/04 12:01 AM:
Thanks Quaoar I try to scan whitout the frame.
Bye
Ercole
Click to expand...
To hold your neg or transparency flat on the glass, use an old film strip <
35mm > taped to the scanner deck at each side and slide your transparency
just under the edge. This should hold down any centre curve. You can also
rig another strip for the bottom of the transparency if needed.
 
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