MTF is calculated by obtaining the value for edge spread function (ESF) and line spread function (LSF) for the edge image of a glass chart and then converting LSF to Fourier. These are calculated for five or more points on the screen, which can then be converted to a graph. MTF is between 0 and 1 and is plotted with opposing frequencies (typically measured using cycles/mm). An MTF value with frequency close to 1 indicates that original resolution has been re-produced nearly perfectly. When the frequency increases, the MTF value falls to 0 and high frequencies can no longer be recognized. When an error occurs in the lens the MTF value is reduced in high frequencies and the edge becomes unclear. Moritex conducts MTF inspections on all lenses to ensure they satisfy customers’ needs for high precision measuring.

Compliant with ISO 12233 slanted-edge methodology