Archived posting to the Leica Users Group, 2002/05/31

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Subject: RE: [Leica] [Fwd: scanner]
From: "Austin Franklin" <darkroom@ix.netcom.com>
Date: Fri, 31 May 2002 16:03:20 -0400

John,

> I still think most over the counter scanners suck or are at least lacking.

In what regard?  Certainly not in density range, and unless you use a tripod
AND use pretty slow speed film and are taking pictures of non-moving
objects, you won't get any better scans from a drum scanner than you will
from something that scans at 4000-5000 SPI.

> The only scanner good enough to pull all the detail out of our
> crappy Leica
> photos is a drum scan.

That depends on a LOT of things, as I mentioned above.  IF you are using a
tripod and using relatively slow film with excellent exposure and
development...  Anything faster than 160 and 4000 SPI will give you most all
of what it's got to give.

> I mean god if you shoot Leica why would you settle
> for anything less than an 11,000dpi 200mb scan of your 35mm frame?!?!?!

Some people use Leicas for other reasons...

And, what on earth are you going to do with that resolution?  You only need
more than, say, 240 PPI to the printer, if you are using Piezo, and at that,
it's very subtle and image dependant.  A 4000 SPI (Samples Per Inch) scan of
a 35mm frame gives you 4000 x 6000, or at 240 PPI to the printer, an output
size of ~ 16 x 25.

The thing a drum scanner will do that a CCD won't, is not give color
artifacts for color film, and it will give you better shadow detail for
slide film...but negative film has a higher dynamic range than slide film
(not exposure latitude, don't confuse the two), and you really, if you're
concerned about image quality, want to shoot negative film.

In practical use, you're getting 40lp/mm which gives you a film resolution
of around 2000 "lines"/inch on the film.  It's a good idea to sample at 2x
that, therefore a 4000 SPI scanner will pretty much give you what you got on
the film.

Austin

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