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[filmscanners] RE: Filmscanners - is this about as goodasitgets?

> From: Julian Robinson
> I have got not argument with this.  The medium is capable of
> recording more
> than fits on the available brightness range of paper.  But digital cameras
> have to process the image somehow to get presentable contrast on
> paper.  If
> they print a whole 9 or 12 stops on paper it looks too low
> contrast, no punch.
> Even if they record as much range as negative film, the fact is that they
> do not display, or make available all this info, while the film does  keep
> it all.  Just as nobody prints all the info stored on a neg because the
> result is appallingly washed out low contrast, no digital camera that I
> have heard of outputs the unadulterated full brightness range
> photo. People
> would be returning them in droves.  So they do clever things to pick which
> range we want to see, and output that instead, just as a photo processor
> does with negs.

But digicams _do_ capture the full brightness range from pitch black to
whatever brightness level saturates the CCD or A/D converter. The top end
may be hard clipped, but the bottom end is limited only by the amount of
noise in the system, not by hard clipping. As long as you don't overexpose,
you capture all the highlight detail, but you still retain the ability to
trade that for shadow detail, or reduced contrast, by adjusting the curves
afterwards in Photoshop.

There may be cheap digicams that boost the contrast artificially to the
point where the shadow detail is completely gone, but that's not the case in
my DiMage 7, at least not when shooting in raw mode. The relationship
between the light power and the numbers isn't logarithmic, with a limit to
how dark you can go, but rather is more nearly linear.


Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com

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