>Lyn A wrote:
>>Alan W wrote:
>
>>On slides it's mostly a moot point unless they are underexposed. <clip>
>>Also Kodachrome is a denser slide generally, which can drop shadows too low
>for many scanners to distinguish properly.
>
>I've found that my Scanwit 2720S does a really good job on well-exposed
>slides and negs, and is almost flawless with landscapes. But the biggest
>problem area in *both* media is where the dynamic range is wide <SNIP>
>and produces serious "noise" with slides and negs alike.
Hi, Lyn.
I'm a bit surprised that you have this problem with the Scanwit. Mine
displays a distinct lack of noise in deep shadows, even in the old K25 and
64. Pete's Photoscientia site also refers to this - I wonder if there is
much variation from scanner to scanner? The only time I begin to see noise
in a slide is if I try to recover an absolute disaster (like 3+ stops
underexposed) when the Acer puts its exposure up to very high levels. Then
I can see some slight streaking in the lower third of the slide
(interestingly my Acer sits on top of my PC - see below*).
Even less of a problem with negs - I *do* get grain-aliasing which seems
much worse on under-exed negs, but that is a little easier to deal with, or
you can always claim it is a deliberate effect! :-(
As a test, I dug up a badly underexposed K25 (the old type) slide that I
had a photo lab make a print from about 5 years ago. The print wasn't
*too* bad.. When I had a go, the Scanwit drew more shadow detail out, and
I got a better print with no 'noise' detectable. Looking closely at the
scan, it does show an effect that looks a bit like grain-aliasing in the
darkest shadows, but the effect is very even, and not 'noise-like'. I
guess it can't be g-a (I hope this thread doesn't start again!), because I
can't see how 2720 dpi would come anywhere near resolving grain effects
from K25..(?)
* Is it possible that the noise is coming from elsewhere, eg a device or
transformer near the Acer or it's cable? I encountered this problem with
my old Olympus scanner..
I would be interested to see the sort of noise you are getting, perhaps you
could even send a small crop to me off-list, or perhaps post it on a
web-site? (On-list attachments are a bit annoying for digest users.)
Regards, MT.
==========================================
Mark Thomas markthom@camtech.net.au
