Apache-Talk @lexa.ru 

Inet-Admins @info.east.ru 

Filmscanners @halftone.co.uk 

Security-alerts @yandex-team.ru 

nginx-ru @sysoev.ru 

   


   


   















      :: Filmscanners
Filmscanners mailing list archive (filmscanners@halftone.co.uk)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Edge to edge focus was Re: filmscanners: Polaroid 4000 dpi



Ed wrote:
>An easy way to test this would be to scan a dusty negative at
>4000 dpi and then seeing if the dust spots are equally focused
>at the edges as in the center.

Another way would be to deliberately scratch a blank or dud frame.  I've
tried this myself when I was concerned about focus on my Nikon.  If you
put a scratch edge to edge, you have a really sharp detail to look at for
focus.  What I discovered was that I really need to use a tripod more often!

Of course - with slides, the type of slide mount may be significant; some
allow the film to bow more, and some are thicker.  Another possible issue
is how quickly you scan; I found with negative strips in the film strip
feeder that they tend to bow more the longer they are in the scanner, heated
by the mechanism.  The end frame in a strip may show better focus on one
side than the other.  With slides in projectors, I found in the past that
the heat of the projector globe would cause the bow in the film to reverse
- I imagine the heat of a scanner could do that same, and if it happened
*after* the scanner did an autofocus, you have a fuzzy scan.

Just some things to consider, anyhow.

Rob


Rob Geraghty harper@wordweb.com
http://wordweb.com






 




Copyright © Lexa Software, 1996-2009.