Underexposure with any bit depth device lowers all values by however many
f-stops you underexpose. Therefore, this has the effect of nudging the
lowest values off the scale where they FALL below the threshold of the
device!
Correct, but adding more bits doesn't change the threshold of the device.
Therefore there IS a relationship to exposure in f-stops!
Nobody's arguing that.
The device stores all data before processing linearly. As you know, the unprocessed image looks anything but "photographic," until properly toned.
Correct. And the darkest tone that the device can capture is assigned to zero. The brightest is assigned to the maximum available value. How much difference there is in those two is dynamic range. How many definable steps there are between the two is a function of bit depth. The more bits, the more definable steps. Add more bits and you don't suddenly make the chip able to see darker or brighter objects, you just define more steps between the limits of the chips ability to respond. Having more bits available allows altering the tone of the linear capture data to a more realistic image tone curve without banding. That's why having more bits is extremely important for wide dynamic range devices but having those bits is not what makes the device a wide range device.
I'm out of here....
Bob Smith
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