X-Git-Url: http://git.kpe.io/?p=cl-photo.git;a=blobdiff_plain;f=dof.lisp;h=d8677d307ad3b40d873f6f4180e66c023f8456a4;hp=917a20df3e34f76c46971343ff97b56f220f978f;hb=HEAD;hpb=532f6e063ec6c9932d02b524473fea4c27043883

diff --git a/dof.lisp b/dof.lisp
index 917a20d..d8677d3 100644
--- a/dof.lisp
+++ b/dof.lisp
@@ -86,43 +86,60 @@ Default resolving power is 5 lpm at 25cm."
 (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)))
+         (hyperfocal (hyperfocal focal-length f-stop coc))
+         (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 (when (/= denominator-1 denominator-2)
+                (/ (- 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 (when far (- far near))))
+    (when (or (>= distance hyperfocal)
+               (and (null far) (>= distance (* hyperfocal 0.99))))
+      (setq near (/ hyperfocal 2)
+            far most-positive-short-float
+            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)))
+         (hyperfocal (hyperfocal focal-length f-stop coc))
+         (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 (when (/= factor-1 factor-2)
+                (+ 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 (when far (- far near))))
+    (when (or (>= distance hyperfocal)
+               (and (null far) (>= distance (* hyperfocal 0.99))))
+      (setq near (/ hyperfocal 2)
+            far most-positive-short-float
+            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)