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[filmscanners] Re: film and scanning vs digital photography
From: "Arthur Entlich" <firstname.lastname@example.org>
Film grain itself is not actual information. it is the random structure
used to create the image on it's smallest level. Grain occurs in three
random manners. Firstly, each color layer is laid down with the silver
halide grains in a completely chaotic manner. Secondly, the grain size
is randomized, and thirdly, the relationship between those factors
between the layers is randomized, as well. This creates a "forgiving"
Hmm. I don't find it forgiving in the slightest. I strongly dislike have the
same ugly texture superimposed on all my images, and for prints I will
actually show people, never use enlargements over 8x.
This means that 35mm is for 8x10, 645 for 12x18, and 6x7 for 16x20.
All of these produce superb quality prints at these sizes. But they wouldn't
be at sizes larger than that.
Meanwhile, my 5D makes just as good 12x18s as 645 does. So there's no point
in shooting 35mm or 645 at this point in history.
Due to the use of the Bayer matrix, the color interpolation required,
and a number of other factors, digital images are intentionally blurred
via electronic filtering. This is why judicious use of unsharp masking
can bring so much detail back to an image.
No, it's _physical_ filter in front of the sensor, called a low-pass, or
antialias, filter. Nothing electronic about it.
The mathematics of discrete sampling tells us that such a filter is required
to achieve correct imaging up to the mathematical resolution limits of the
sensor. But you knew that.
What I've recently come to realize is that low-pass filtering _improves_
resolution by removing jaggies. Just as antialiasing in font display
improves the apparent resolution of fonts on the screen, antialiasing in
discrete capture allows the sensor to show the position of sharp edges and
lines more accurately than happens in non-antiliased cameras.
The reason the debate regarding image resolution - film versus digital -
continues, is because instrumentation can't really answer it. Yes,
numbers of line pairs can be read, etc. but that isn't how we perceive.
So far, so good.
Our eyes prefer random analogue and in spite of the defects in this
method, we have built in filters to deal with that because nature is
designed around random noise.
Your eyes, maybe. Mine don't like random noise. It's a good thing that film
scales up to much larger formats than digital. I really don't understand how
people can stand 5x7s from 35mm Tri-X.
So, this debate cannot be answered by machines. It can only be answered
by human consensus.
Yep. And 12x18 images from 24x36mm of film are unacceptable, whatever film
is used. (And embarrassing if the bloke who made the print displayed next to
yours used MF or 12MP digital.)
David J. Littleboy
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