RE: filmscanners: Magnification of light

["Austin Franklin" <darkroom@ix.netcom.com>]

> Seems to me that there are *two* factors at work here, not mutually
> exclusive. The Dmax wouldn't explain why dust effects are amplified--and
> they seem to be, by empirical observation of several members.

I have no idea about this, but it was not part of what I was talking about.

> Nor
> would the
> dynamic range explain why light appears to be magnified in
> contrast to dark
> areas (although that's also a function of the human eye, and not easily
> quantifiable).

Dynamic range does explain that.  In fact, that is what dynamic range is.
Think of it like your hearing...now that you're older, you can't hear high
frequencies, but when you were younger you could...yet the amplitude of the
high frequencies hasn't changed...  That is because as you get older, the
dynamic range of your ears decreases.

Dynamic range is the breadth of which you can sense.  A wider dynamic range
of a sensor means it extends its limits either up or down (or both) the
spectrum.  Since film only has a dynamic range of high 2's to low 3's for
color print film, and the CCD in the camera has a dynamic range of mid 3's,
it will be able to discern dark detail better than negative film.  It's
simple math.  Do you know what DMax means, mathematically that is?

> I might very well be missing something, here,

It could be you may be don't understand what dynamic range and/or density
ratio values are?  If not, I can explain it...