(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, 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.
Reference: http://www.vanwalree.com/optics/dofderivation.html"
(let* ((aperture (/ focal-length f-stop))
- (pd (* aperture pupil-factor))
- (numerator (* coc (- distance focal-length) (+ focal-length (* pupil-factor (- distance focal-length)))))
- (d1 (* pupil-factor coc (- distance focal-length)))
- (d2 (* pd focal-length))
- (front-dof (/ numerator (+ d1 d2)))
- (rear-dof (/ numerator (- d1 d2)))
+ (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 (+ front-dof rear-dof)))
- (values front-dof rear-dof depth mag infinity-blur-diameter)))
+ (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 dof, far dof, total dof, near point, far point, magnification,
+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 (* coc (- distance focal-length) (+ focal-length (* (- distance focal-length)))))
- (d1 (* coc (- distance focal-length)))
- (d2 (* aperture focal-length))
- (front-dof (/ numerator (+ d1 d2)))
- (rear-dof (/ numerator (- d1 d2)))
+ (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 (+ front-dof rear-dof)))
- (values front-dof rear-dof depth mag infinity-blur-diameter)))
+ (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)))
(defun dof (focal-length f-stop distance coc &key (units :mm) (pupil-factor 1))
"Returns the Depth of Field.
Input: FOCAL-LENGTH, F-STOP, DISTANCE, CIRCLE-OF-CONFUSION.
-Output: NEAR-DOF, FAR-DOF, TOTAL-DOF, MAGNIFICATION, BLUR-SIZE-OF-INFINITY-POINT-IN-MM."
+Output: NEAR-POINT, FAR-POINT, TOTAL-DOF, MAGNIFICATION, BLUR-SIZE-OF-INFINITY-POINT-IN-MM."
(multiple-value-bind (near-point far-point total-dof mag blur)
(dof-mm focal-length f-stop (length->mm distance units) coc
:pupil-factor pupil-factor)