(defun dof-mm (focal-length f-stop distance coc &key (pupil-factor 1))
"Returns depth of field based on focal-length, f-stop, distance, and coc.
Six values are returned:
-near dof, far dof, total dof, near point, far point, magnification,
-blur size at infinity (mm).
+near point, far point, total dof, magnification, blur size at infinity (mm).
Circle of confusion can either be a number or keyword designating format."
(let* ((aperture (/ focal-length f-stop))
(numerator-1 (* (- pupil-factor 1) (- distance focal-length)