Dynamic Range
The span between the brightest and darkest tones a camera can record in a single frame while keeping usable detail at both ends.
Formula / rule
DR = log₂(full-well / read noise)
Measured in
stops (EV)
In depth
The upper limit is set by how many electrons a photosite can hold before saturating; the lower limit by the noise floor of the readout. A modern full-frame sensor manages roughly fourteen stops at base ISO, falling by about one stop for every stop of ISO gain. Human vision, adapting continuously, comfortably exceeds twenty.
Examples in practice
A backlit forest can span eighteen stops from sunlit sky to deep shade — beyond any single frame, which is why bracketing or a graduated filter is needed.