+(defun coc-airy (f-stop &optional (wavelength 0.000512))
+ "Return the circle of confusion based on the airy disk."
+ (float (/ 1 (rayleigh-limit f-stop wavelength))))
+
+(defun rayleigh-limit (f-stop &optional (wavelength 0.0005))
+ "Returns the rayleigh limit in line pairs per mm (MTF 9%) as well as the MTF50"
+ (let ((rayleigh (float (/ 1 1.22 f-stop wavelength))))
+ (values rayleigh (* 0.46 rayleigh))))
+
+(defun maximum-sharpness-aperture (format &optional (wavelength 0.0005))
+ (multiple-value-bind (coc-w coc-h lpm-w lpm-h) (coc-pixels-format format)
+ (declare (ignore coc-w coc-h))
+ (/ 1. (* 1.22 wavelength (/ (min lpm-w lpm-h) 0.46)))))
+
+(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 point, far point, total dof, magnification, blur size at infinity (mm).
+Circle of confusion can either be a number or keyword designating format.
+Reference: http://www.vanwalree.com/optics/dofderivation.html"
+ (let* ((aperture (/ focal-length f-stop))
+ (numerator-1 (* (- pupil-factor 1) (- distance focal-length)
+ coc focal-length))
+ (numerator-2 (* pupil-factor aperture focal-length distance))
+ (denominator-1 (* pupil-factor coc (- distance focal-length)))
+ (denominator-2 (* pupil-factor aperture focal-length))
+ (near (/ (+ numerator-1 numerator-2)
+ (+ denominator-1 denominator-2)))
+ (far (/ (- numerator-1 numerator-2)
+ (- denominator-1 denominator-2)))
+ (mag (float (/ focal-length (- distance focal-length))))
+ (infinity-blur-diameter (/ (* mag focal-length) f-stop))
+ (depth (- far near)))
+ (when (and (< far 0) (> distance focal-length))
+ (setq far most-positive-short-float)
+ (setq depth most-positive-short-float))
+ (values near far depth mag infinity-blur-diameter)))
+
+;; Simplified calculation for symmetric lens
+(defun dof-symmetric-mm (focal-length f-stop distance coc)
+ "Returns depth of field based on focal-length, f-stop, distance, and coc.
+Six values are returned:
+near point, far point, total dof, near point, far point, 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 (* distance coc (- distance focal-length)))
+ (factor-1 (* focal-length aperture))
+ (factor-2 (* coc (- distance focal-length)))
+ (near (- distance (/ numerator (+ factor-1 factor-2))))
+ (far (+ distance (/ numerator (- factor-1 factor-2))))
+ (mag (magnification :focal-length focal-length :object-distance distance :units :mm))
+ (infinity-blur-diameter (/ (* mag focal-length) f-stop))
+ (depth (- far near)))
+ (when (and (< far 0) (> distance focal-length))
+ (setq far most-positive-short-float)
+ (setq depth most-positive-short-float))
+ (values near far depth mag infinity-blur-diameter)))