Camera Raw/profiling
Camera Raw/profiling
- Subject: Camera Raw/profiling
- From: "LensArtGallery" <email@hidden>
- Date: Mon, 24 Feb 2003 00:10:50 -0800
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Message: 14
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Date: Mon, 24 Feb 2003 14:26:06 +1100
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From: Graeme Gill <email@hidden>
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To: email@hidden
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Subject: Re: Camera Raw
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It seems desirable that there be a way of capturing
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and representing an input devices color behaviour in a way that
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is valid over its full exposure and sensor dynamic range
I'm sure there are many ways to accomplish this feat mathematically, but
would a chart that simulated the full dynamic range of the sensor be the
most desirable? I can think of a several ways this could be accomplished.
As an example: one simple way it's done with B&W film, is to use a "zone
board", which is a 7 ft. long board with a tin can and light bulb on one end
with patches placed along the board precisely to simulate the entire range
of tones the film is capable of reproducing, as the light falls off from one
end of the board to the other (11 stop range) in a darkened room. The film
is read on a densitometer and adjustments are made untill the entire range
of the film is acurately calibrated through different chemical/time
/temperature combinations for various contrast levels. Although this method
seems klunky and primitive, it is absolutely accurate, predictable, reliable
and requires very little math.
I just wonder if a way of capuring the entire range of tones for a given
sensor wouldn't be found to be superior to current methods.
A possible way might be to light the chart with flash rather than continous
light. An 11 stop range (or more) could be simulated by tripping the flash
from once to multiple times and variying the lens diaphram.
Rob Scheid
LensArt Gallery
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