+(defun coc (imager-size &key (lpm 5) (minimum-distance 250)
+ (viewing-distance 250)
+ (print-size (output-dimensions :8x10in)))
+ "Returns circle of confusion in mm and print magnification for a format.
+Default resolving power is 5 lpm at 25cm."
+
+ (let* ((imager-diagonal (diagonal (car imager-size) (cdr imager-size)))
+ (print-diagonal (diagonal (car print-size) (cdr print-size)))
+ (resolution-factor (/ (* lpm print-diagonal minimum-distance)
+ (* imager-diagonal viewing-distance)))
+ (coc (/ 1.0d0 resolution-factor))
+ (print-magnification (/ print-diagonal imager-diagonal)))
+ (values coc print-magnification)))