HDR Photography By Jakub Kubica

The human perception of brightness is well approximated by a Steven's power law, which over a reasonable range is close to logarithmic, as described by the Weber–Fechner law, which is one reason that logarithmic measures of light intensity are often used.
Scanning film
In contrast to analogue photographs, color negatives and slides consist of multiple film layers that respond to light differently. As a consequence, transparent originals (especially color negatives) feature a very high dynamic range.