In this and the previous article I discuss how Modulation Transfer Functions (MTF) obtained from every raw color plane of a Bayer CFA in isolation can be combined to provide a meaningful composite MTF curve for the imaging system as a whole.  There are two main ways to accomplish this objective:

• an input-referred linear Hardware System MTF () that reflects the mix of spectral information captured in the raw data, divorced from downstream color science; and
• an output-referred linear Luminance System MTF () that reflects the luminance channel of the image as neutrally displayed.

Both are valid on their own, though the weights of the former are fixed for any Bayer sensor while the latter are scene, camera/lens and illuminant dependent.  For this reason I usually prefer input-referred weights as a first pass when comparing cameras and lens hardware in similar conditions. Continue reading System MTF from Bayer Sensors →