Raw Bit Depth
The number of bits used to record each photosite's value in a raw file, determining how many tonal levels are captured.
Formula / rule
Levels = 2^bits
Measured in
bits
In depth
Twelve bits gives 4,096 levels per channel, fourteen gives 16,384 and sixteen gives 65,536. Because sensor response is linear, the extra levels land mostly in the highlights, so the practical benefit of higher bit depth appears in the shadows only after heavy lifting. Many cameras drop to 12 bits in high-speed burst modes.
Examples in practice
Shooting 14-bit rather than 12-bit raw shows its advantage when shadows are pushed three stops or more.