View source for Camera response curve

The '''camera response curve''' is {{Glossary|a curve showing the relation between amount of incoming light and image pixel values of a digital camera.|1}}

This curve is sometimes also called '''Opto-Electrical Transfer Function'''. 

Although optical sensors work quite linear (a certain amount of photons coming in causes a proportional amount of electrons in the sensor cell), the resulting pixel values are not proportional to the amount of incoming light. This might have several reasons: 
* The analog-digital converter might not work linearly. 
* A [[Gamma]] correction is applied.
* A correction is applied to make the image more visually appealing
* A white balance is applied to compensate for different light temperature

While the first reason applies to all kinds of images, the other ones apply to non-RAW ([[JPEG]], [[TIFF]]) images only. [[RAW]] images should contain linear sensor data.

The '''camera response curve''' is an issue mainly in [[HDR]] generation where it is necessary to have linear (proportional to light) input data. Non-linear data (= a badly estimated camera response curve) will result in banding in contrast gradients (f.e. around bright lights).