The optical transfer function (OTF) of an optical system such as a camera, microscope, human eye, or projector is a scale-dependent description of their imaging contrast. Its magnitude is the image contrast of the harmonic intensity pattern,, as a function of the spatial frequency,, while its complex argument indicates a phase shift in the periodic pattern. The optical transfer function is us. Definition and related conceptsSince the optical transfer function (OTF) is defined as the Fourier transform of the point-spread function (PSF), it is generally speaking a function of. The projection of a specific per. A perfect lens system will provide a high contrast projection without shifting the periodic pattern, hence the optical transfer function is identical to the modulation transfer function. Typically the contrast will reduce gra.