Archived posting to the Leica Users Group, 2001/07/24

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Subject: Re: [Leica] Scanning
From: "Mxsmanic" <mxsmanic@hotmail.com>
Date: Tue, 24 Jul 2001 09:18:35 +0200
References: <NABBLIJOIFAICKBIEPJJEEGEKLAA.darkroom@ix.netcom.com>

Austin Franklin writes:

> 2700DPI only approaches the limit of quite
> grainy films.

2700 dpi is 53 lp/mm.  It is very difficult to achieve 53 lp/mm with handheld
photographs because of camera shake (and most of my photos are handheld).
Additionally, most lenses--even most Leica lenses--show rapidly deteriorating
modulation transfer beyond 40 lp/mm, and most films are not much better,
declining rapidly around 50 lp/mm.  If you disagree, a quick look at the actual
MTF charts for lenses and film will reveal that 53 lp/mm is plenty for most
photographs with most lenses (Leica or otherwise) on most films.

> 4000DPI approaches the grain of 160ASA
> film, and 5080 of 100ASA...

Under ideal conditions, perhaps.  But in practice, one rarely gets that far.

I've scanned thousands of photos, too.  In 99% of them, it is very clear that
the resolution in the photo is not anywhere near the 35 lp/mm limit of the
scanner.  In fact, it is surprising to see a photo so clear that every pixel is
being fully utilized at 2700 dpi.  With a tripod, the limits are more likely to
be reached (with a good lens and fine film), but I almost never shoot anything
on a tripod.

In reply to: Message from "Austin Franklin" <darkroom@ix.netcom.com> (RE: [Leica] Scanning)