1 ;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10; Package: photo -*-
2 ;;;; *************************************************************************
3 ;;;; FILE IDENTIFICATION
6 ;;;; Purpose: Depth of field functions for cl-photo
7 ;;;; Programmer: Kevin M. Rosenberg
8 ;;;; Date Started: April 2005
12 ;;;; This file, part of cl-photo, is Copyright (c) 2005 by Kevin Rosenberg.
13 ;;;; Rights of modification and redistribution are in the LICENSE file.
15 ;;;; *************************************************************************
19 ;; Based on http://www.photostuff.co.uk/dofmstr.htm
21 (defun coc-format (format &key (lpm 5) (minimum-distance 250)
22 (viewing-distance 250)
23 (print-size (format-dimensions :8x10in)))
24 "Returns circle of confusion in mm and print magnification for a format.
25 Default resolving power is 5 lpm at 25cm."
27 (let* ((format-size (format-dimensions format))
28 (format-diagonal (diagonal (car format-size) (cdr format-size)))
29 (print-diagonal (diagonal (car print-size) (cdr print-size)))
30 (resolution-factor (/ (* lpm print-diagonal minimum-distance)
31 (* format-diagonal viewing-distance)))
32 (coc (/ 1.0d0 resolution-factor))
33 (print-magnification (/ print-diagonal format-diagonal)))
34 (values coc print-magnification)))
36 (defun coc-sensor (format nx ny)
37 "Returns circle of confusion based on pixel size."
38 (let* ((dim (format-dimensions format))
39 (pixel-width (/ (car dim) nx))
40 (pixel-height (/ (cdr dim) ny)))
41 (values (coerce (* 2 pixel-width) 'float)
42 (coerce (* 2 pixel-height) 'float))))
44 (defun coc-sensor-camera (camera &key (format :aps))
45 (let ((dim (sensor-dimensions camera :format format)))
46 (coc-sensor format (car dim) (cdr dim))))
48 (defun sensor-dimensions-megapixels (format megapixels)
49 (let* ((dim (format-dimensions format))
50 (aspect-ratio (/ (car dim) (cdr dim)))
51 (width (round (sqrt (* aspect-ratio 1000000 megapixels)))))
52 (cons width (round (/ width aspect-ratio)))))
54 (defun sensor-dimensions (camera &key (format :aps))
59 (:d2x (cons 4288 2848))
60 (:d2x (cons 2484 1242))
61 (:d70 (cons 3008 2000))
64 (:1d (cons 2464 1648))
65 (:1d2 (cons 3504 2336))
66 (:1ds (cons 4064 2704))
67 (:1ds2 (cons 4992 3328))
71 (sensor-dimensions-megapixels format camera))))
73 (defun coc-airy-disk (f-stop)
74 "Return the circle of confusion based on the airy disk."
75 (let ((airy (/ f-stop 1500)))
76 (coerce (* 2 airy) 'float)))
78 (defun dof (focal-length f-stop distance coc)
79 "Returns depth of field as fives values:
80 near dof, far dof, total dof, near point, far point.
81 Circle of confusion can either be a number or keyword designating format."
82 (let* ((aperature (/ focal-length f-stop))
83 (numerator (* distance coc (- distance focal-length)))
84 (factor-1 (* focal-length aperature))
85 (factor-2 (* coc (- distance focal-length)))
86 (near (/ numerator (+ factor-1 factor-2)))
87 (far (/ numerator (- factor-1 factor-2)))
89 (values near far depth (- distance near) (+ distance far))))
91 (defun dof-feet (focal-length f-stop distance coc)
92 (multiple-value-bind (near-dof far-dof total-dof near-point far-point)
93 (dof focal-length f-stop (feet->mm distance) coc)
94 (values (mm->feet near-dof) (mm->feet far-dof) (mm->feet total-dof)
95 (mm->feet near-point) (mm->feet far-point))))
97 (defun dof-meters (focal-length f-stop distance coc)
98 (multiple-value-bind (near-dof far-dof total-dof near-point far-point)
99 (dof focal-length f-stop (* 1000 distance) coc)
100 (values (* 0.001 near-dof) (* 0.001 far-dof) (* 0.001 total-dof)
101 (* 0.001 near-point) (* 0.001 far-point))))
103 (defun hyperfocal (focal-length f-stop coc)
104 (+ focal-length (/ (* focal-length focal-length) (* f-stop coc))))
106 (defun hyperfocal-feet (focal-length f-stop coc)
107 (mm->feet (hyperfocal focal-length f-stop coc)))