Dynamic range and RAW file "bit depth"

Started Jan 25, 2014 | Questions thread
olliess Senior Member • Posts: 1,349
Re: bit depth affects PRECISION, not dynamic range so much

RussellInCincinnati wrote:

Then hopefully the Nikon D800 raw file format lavishes many more of the 8192 different numbers on representing the upper brightness range with precision, than the format dedicates to representing the darkest parts of the scene. The firmware designer could declare that the camera will store scene exposure values ranging from 13.5 to 14.5 EV in the raw files using all the numbers between 4096 and 8191, obviously with great precision, for example. And reserve the lower raw format values to represent all the scene brightnesses below 13.5 with far less precision, etc.

The brightest parts of the scene have more noise (but better signal/noise) than the lowest parts. More values would just go into "encoding the noise." It would make more sense to have wider spacing values as the values increase, e.g., something close to logarithmic spacing. (I believe this is what the old Compressed NEF format did with a lookup table).

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