Based on "Bokeh calculator" by syamastro - http://www.physics.mcmaster.ca/~syam/Photo/bokeh.html
When result is less than one, there is no bokeh effect (the background is completely sharp); bokeh becomes obvious at 10 and is huge when result is larger than 100 (total background blur).
This gist references to some data arrays at https://gist.github.com/gists/1327415
| // all arguments in _meters_ | |
| function /*bokeh*/( | |
| a, // distance to target | |
| b, // circle of confusion @see https://gist.github.com/gists/1327415 - z_coc.js for details | |
| c, // aperture (f/2.8 - 2.8 etc) | |
| d, // lenses focal | |
| f, // camera sensor height @see https://gist.github.com/gists/1327415 - z_sensor.js for details | |
| x, // distance from target to background, default 1e6 (only finity positive number is allowed) | |
| z | |
| ){ | |
| x = x || 1e6; | |
| return x / ((z = ((a * f / d) / f + 1) * d) + x) * d * d / c / (z - d) / b | |
| }; |
| function(a,b,c,d,e,f,g){return f=f||1e6,f/((g=(a*e/d/e+1)*d)+f)*d*d/c/(g-d)/b} |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright (C) 2011 Mikhail Davydov <azazel.private@gmail.com> | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE FUCK YOU WANT TO. |
| { | |
| "name": "bokeh_calculator", | |
| "description": "A bokeh number (background blur value) calculator", | |
| "keywords": [ | |
| "bokeh", | |
| "photo", | |
| "calculator" | |
| ] | |
| } |
| <!DOCTYPE html> | |
| <title>Photo Frame</title> | |
| <div>Expected value: <b>55.0600902713579</b></div> | |
| <div>Actual value: <b id="ret"></b></div> | |
| <script> | |
| var CIRCLES_OF_CONFUSION = { | |
| "Canon 5D (Mark II)": 0.03 | |
| /* ... */ | |
| }; | |
| var SENSOR_SIZES = { | |
| "Canon 5D (Mark II)": [36, 24] | |
| /* ... */ | |
| }; | |
| var CAMERA_NAME = "Canon 5D (Mark II)", | |
| DISTANCE = 3, // m | |
| COC = CIRCLES_OF_CONFUSION[CAMERA_NAME], // mm | |
| APERTURE = 2.8, | |
| FOCAL = 135, // mm | |
| DISTANCE_FROM_TARGET_TO_BACKGROUND = 10, // m | |
| SENSOR_HEIGHT = SENSOR_SIZES[CAMERA_NAME][1]; // mm | |
| var bokeh = function(a,b,c,d,e,f,g){return f=f||1e6,f/((g=(a*e/d/e+1)*d)+f)*d*d/c/(g-d)/b}; | |
| var result = bokeh(DISTANCE, COC / 1e3, APERTURE, FOCAL / 1e3, SENSOR_HEIGHT / 1e3, DISTANCE_FROM_TARGET_TO_BACKGROUND); | |
| document.getElementById("ret").innerHTML = result; | |
| </script> |