Modulation transfer function (MTF) is a tool for assessing the resolution behavior of individual components of a total imaging system. The primary metric of resolution in imaging is MTF. The perception of sharpness depends, to a lesser degree, on the resolution and more on the micro contrast in the image, which is called acutance. A high-resolution image with low contrast may look less sharp than a low resolution image with high contrast. Lens system contrast varies as a function of the spatial frequency of the stimuli that they attempt to transmit. As Nyquist theory and deBayer in practice show us, Bayer pattern sensors yield less real world resolution than their photosite count. MTF is very important because in its association of lens contrast with spatial detail it is conveying a great deal of information about the image sharpness that that lens can deliver. Aliasing sometimes shows up as an inaccurate, annoying, and distracting Moiré pattern in high frequency detail areas.