I am trying to learn the ACES workflow, and need some help with this topic.
It is my understanding that the Input Transforms are made for each camera (or camera-setting combination) so that the resulting linear values all represent the same physical quantity. So if I shoot the same scene with two different sensors, the results should be virtually identical, all other factors considered. What I would like to know, is how do these values correlate with real illumimance as experienced by the sensor?
Of course, to get useful information about the actual scene, one would have to adjust this data according to the exposure time and lens’ transmission and aperture. But the sensor’s response to the light it receives should be accurately described by the manufacturer’s Input Transform. How do I convert from one to another? Even better if anyone could point out where this is documented.