ABSTRACT
If an “ideal” film or sensor was truly linear, it would have an equal increase in density for every increase in exposure: doubling the amount of light in the scene would exactly double the brightness of the final image. A non-linear response curve isn’t really “accurately” reproducing the scene in front of the camera. Human vision perceives brightness in a non-linear fashion; it works out to a gamma of about.42, which is, by coincidence, the inverse of 2.4. Some people think that gamma just means contrast and nothing more, but this isn’t really true. In HD cameras, Gamma is a key adjustment that is available to the operator. Manufacturers have several versions of gamma encoding variously called Hypergamma, Cinegamma, Video Rec, Film Rec, or low contrast curve, which are designed to extend the dynamic range of the camera. RedlogFilm is a log encoding that’s designed to remap the original 12-bit camera data to the standard Cineon curve.
