MTF is defined as the Fourier transform (FT) of the point spread function (PSF). This concept applies to a linear system that is shift invariant. In practice, MTF is usually measured in two orthogonal directions using FT of the line spread function.

MTF and CTF are applicable to almost any printing technology. Contrast Transfer Function (CTF) is the preferred term for printed sample measurements. The term MTF is really more appropriate for optical components characterization. There are three components in CTF, 1) contrast, 2) transfer, and 3) function.

The production of point light sources and line light sources requires a certain precision and is relatively complex, so the method of obtaining ESF by edge imaging is generally used to calculate MTF, which is called slanted-edge method.

MTF measures a lens' ability to transfer the contrast of a sample to an image using spatial frequency (resolution). Spatial frequency indicates the number of line pairs (i.e., one black and one white line) per millimeter (lp/mm).