Dynamic Range (DR) in Photography usually refers to the linear working signal range, from darkest to brightest, that the imaging system is capable of capturing and/or displaying. It is expressed as a ratio, in stops:
![\[ DR = log_2(\frac{Maximum Acceptable Signal}{Minimum Acceptable Signal}) \]](https://i0.wp.com/www.strollswithmydog.com/wordpress/wp-content/ql-cache/quicklatex.com-c691db4feaf1e0b8c2cf50cb84b5b7bf_l3.png?resize=321%2C41&ssl=1 "Rendered by QuickLaTeX.com")
It is a key Image Quality metric because photography is all about contrast, and dynamic range limits the range of recordable/ displayable tones. Different components in the imaging system have different working dynamic ranges and the system DR is equal to the dynamic range of the weakest performer in the chain.