The "camera response function" refers to how the radiance arriving on image film/CCD, after passing through the lens, is transformed to actual pixel "brightness" values. The easiest and usual transformation that we apply is the simple brightness+gamma. But in practice, where photo cameras are involved, a more complex formula takes place usually "coded" from manufacturers themselves in order to compress a high dynamic range image into a low dynamic range (usually jpeg) photo.

What the above means is that we can now enjoy realistic non-linear display of the results - other than standard "gamma" - easily selectable from a drop-down list that makes the final image matching better the one coming from a real camera.

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