Zeiss formula
In photographic optics, the Zeiss formula is a supposed formula for computing a circle of confusion (CoC) criterion for depth of field (DoF) calculations. The formula is c = d / 1730 {\displaystyle c=d/1730} , where d {\displaystyle d} is the diagonal measure of a camera format, film, sensor, or print, and c {\displaystyle c} the maximum acceptable diameter of the circle of confusion.