EV Calculation

The contrast ratio of the luminances of the brightest object to the darkest one, whose details are capable of being discerned/produced. The real world has a luminance range of around 10^-6 to 10^6 cd/m^2, while a computer monitor has a range of around 1-400cd/m^2. In photography, dynamic range is described in terms of E.V. differences (or stops) between the most and least luminous regions of a scene, with an EV difference of one corresponding to a doubling/halving of light and by extension, a contrast ratio of two. Mathematically, contrast ratio = 2^EV. The dynamic range of both sensors and monitors is significantly lower than that of the human eye.

Instructions on how to use the table below to compute the EV for HDR photography:

To compute the EV enter:

1.    ‘Shutter Speed’  in seconds or fractions of a second.

2.    ‘Aperture’ values.

3.    ‘ISO’ values.

4.    Click on the ‘Compute EV’ button to get ‘Computed EV’ values.

<?php<!-- [et_pb_line_break_holder] --> /*<!-- [et_pb_line_break_holder] --> Template Name: HDR Exposure Form<!-- [et_pb_line_break_holder] --> */<!-- [et_pb_line_break_holder] -->?><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --><?php<!-- [et_pb_line_break_holder] -->// PHP PART 1 GOES HERE (PROCESSING) <!-- [et_pb_line_break_holder] -->$et0_error = '';<!-- [et_pb_line_break_holder] -->$apr0_error = '';<!-- [et_pb_line_break_holder] -->$isosen0_error = '';<!-- [et_pb_line_break_holder] -->$message_error = '';<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] -->//if($_REQUEST['c_submitted']){<!-- [et_pb_line_break_holder] -->if($_REQUEST['c_submit']){<!-- [et_pb_line_break_holder] --> //check Exposure time (seconds)<!-- [et_pb_line_break_holder] --> if(trim($_REQUEST['et0'] == "")){<!-- [et_pb_line_break_holder] --> //it's empty<!-- [et_pb_line_break_holder] --> $et0_error = __('You forgot to fill in the Shutter Speed (seconds)');<!-- [et_pb_line_break_holder] --> $error = true;<!-- [et_pb_line_break_holder] --> }else{<!-- [et_pb_line_break_holder] --> //its ok<!-- [et_pb_line_break_holder] --> $et0 = trim($_REQUEST['et0']);<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //check F-number<!-- [et_pb_line_break_holder] --> if(trim($_REQUEST['apr0'] === "")){<!-- [et_pb_line_break_holder] --> //it's empty<!-- [et_pb_line_break_holder] --> $apr0_error = __('Your forgot to fill in the Aperture');<!-- [et_pb_line_break_holder] --> $error = true;<!-- [et_pb_line_break_holder] --> }else{<!-- [et_pb_line_break_holder] --> //it's ok<!-- [et_pb_line_break_holder] --> $apr0 = trim($_REQUEST['apr0']);<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //check ISO<!-- [et_pb_line_break_holder] --> if(trim($_REQUEST['isosen0'] === "")){<!-- [et_pb_line_break_holder] --> //it's empty<!-- [et_pb_line_break_holder] --> $isosen0_error = __('You forgot to fill in the ISO');<!-- [et_pb_line_break_holder] --> $error = true;<!-- [et_pb_line_break_holder] --> }else{<!-- [et_pb_line_break_holder] --> //it's ok<!-- [et_pb_line_break_holder] --> $isosen0 = trim($_REQUEST['isosen0']);<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //if no errors occured<!-- [et_pb_line_break_holder] --> if($error != true) {<!-- [et_pb_line_break_holder] --> /* Test code below: Does no processing */<!-- [et_pb_line_break_holder] --> $comev0 = ($et0 * $apr0);<!-- [et_pb_line_break_holder] --> $comev1 = ($et1 * $apr1);<!-- [et_pb_line_break_holder] --> $comev2 = ($et2 * $apr2);<!-- [et_pb_line_break_holder] --> <!-- [et_pb_line_break_holder] --> $_REQUEST['comev0'] = $comev0;<!-- [et_pb_line_break_holder] --> $_REQUEST['comev1'] = $comev1;<!-- [et_pb_line_break_holder] --> $_REQUEST['comev2'] = $comev2;<!-- [et_pb_line_break_holder] --> <!-- [et_pb_line_break_holder] --> $_REQUEST['comev0'] = '7';<!-- [et_pb_line_break_holder] --> $_REQUEST['comev1'] = '7';<!-- [et_pb_line_break_holder] --> $_REQUEST['comev2'] = '7';<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] -->}<!-- [et_pb_line_break_holder] -->?><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --><?php get_header(); ?><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --><!-- jQuery GOES HERE (VALIDATION AND AJAX PROCESSING) --><!-- [et_pb_line_break_holder] --><script type="text/javascript"><!-- [et_pb_line_break_holder] --><!--//--><![CDATA[//><!--<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> jQuery(document).ready(function(){<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> jQuery('#hdrexposure-form form').submit(function(e){<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //prevent the normal processing<!-- [et_pb_line_break_holder] --> e.preventDefault();<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //delete the errors (so we don't get duplicates ')<!-- [et_pb_line_break_holder] --> jQuery("#hdrexposure-form .error").remove();<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //declaring and setting vars<!-- [et_pb_line_break_holder] --> var value, theID, empty_error,isosen0_error, error, emailReg;<!-- [et_pb_line_break_holder] --> empty_error = '<p class="error">This field is required</p>';<!-- [et_pb_line_break_holder] --> //iso0_error = '<p class="error">The email you entered is not valid</p>';<!-- [et_pb_line_break_holder] --> error = false;<!-- [et_pb_line_break_holder] --> //emailReg = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/; <!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //validating<!-- [et_pb_line_break_holder] --> jQuery('#hdrexposure-form textarea, #hdrexposure-form input[type=text]').each(function(){<!-- [et_pb_line_break_holder] --> value = jQuery(this).val();<!-- [et_pb_line_break_holder] --> theID = jQuery(this).attr('id');<!-- [et_pb_line_break_holder] --> if(value == ''){<!-- [et_pb_line_break_holder] --> jQuery(this).parent().append('<p class="error">'+empty_error+'</p>');<!-- [et_pb_line_break_holder] --> error = true;<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> //if(theID == 'c_email' && value != '' && !emailReg.test(value)){<!-- [et_pb_line_break_holder] --> // jQuery(this).parent().append('<p class="error">'+iso0_error+'</p>');<!-- [et_pb_line_break_holder] --> // error = true;<!-- [et_pb_line_break_holder] --> //}<!-- [et_pb_line_break_holder] --> });<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> //send email and loaded message<!-- [et_pb_line_break_holder] --> if(error == false){<!-- [et_pb_line_break_holder] --> //jQuery('#hdrexposure-form').load('<?php the_permalink(); ?> .email-sent', jQuery('#hdrexposure-form form').serialize());<!-- [et_pb_line_break_holder] --> var max = 9;<!-- [et_pb_line_break_holder] --> var min = 3;<!-- [et_pb_line_break_holder] --> var shown = 3;<!-- [et_pb_line_break_holder] --> var et = new Array(max);<!-- [et_pb_line_break_holder] --> var apr = new Array(max);<!-- [et_pb_line_break_holder] --> var isosen = new Array(max);<!-- [et_pb_line_break_holder] --> var evn = new Array(max);<!-- [et_pb_line_break_holder] --> wrong_value = false;<!-- [et_pb_line_break_holder] --> for (i=0; i<shown; i++)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> et[i] = document.getElementById("et"+i).value;<!-- [et_pb_line_break_holder] --> apr[i] = document.getElementById("apr"+i).value;<!-- [et_pb_line_break_holder] --> isosen[i] = document.getElementById("isosen"+i).value;<!-- [et_pb_line_break_holder] --> <!-- [et_pb_line_break_holder] --> //document.getElementById("comev"+i).value = et[i] * apr[i];<!-- [et_pb_line_break_holder] --> if (et[i].indexOf('/',0)>0)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> var etf1 = et[i].split('/');<!-- [et_pb_line_break_holder] --> et[i] = etf1[0]/etf1[1];<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> if (isNaN(et[i]) | et[i] <= 0) <!-- [et_pb_line_break_holder] --> { wrong_value = true;<!-- [et_pb_line_break_holder] --> document.getElementById("et"+i).value = 'Enter Seconds';<!-- [et_pb_line_break_holder] --> document.getElementById("comev"+i).value = '0';<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> if (isNaN(apr[i]) | apr[i] <= 0)<!-- [et_pb_line_break_holder] --> { wrong_value = true;<!-- [et_pb_line_break_holder] --> document.getElementById("apr"+i).value = 'Enter Aperture';<!-- [et_pb_line_break_holder] --> document.getElementById("comev"+i).value = '0';<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> if (isNaN(isosen[i]) | isosen[i] <= 0)<!-- [et_pb_line_break_holder] --> { wrong_value = true;<!-- [et_pb_line_break_holder] --> document.getElementById("isosen"+i).value = 'Enter ISO';<!-- [et_pb_line_break_holder] --> document.getElementById("comev"+i).value = '0';<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> if (wrong_value == true)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> //alert("Error! Not valid input data!");<!-- [et_pb_line_break_holder] --> alert("Input Shutter Speed in seconds as a Numeric value, Decimal or Fraction (Example: 2, 0.25, 1/15); Aperture & ISO.");<!-- [et_pb_line_break_holder] --> for (i=0; i<shown; i++)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> //document.getElementById("comev"+i).value = 'ERROR';<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> if (wrong_value == false)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> var middle = 0; //JPP<!-- [et_pb_line_break_holder] --> //var test = 0;<!-- [et_pb_line_break_holder] --> var evns = new Array(shown);<!-- [et_pb_line_break_holder] --> for (i=0; i<shown; i++)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> evn[i] = Math.log(et[i]/(apr[i]*apr[i])*isosen[i]/100.0) / Math.log(2);<!-- [et_pb_line_break_holder] --> evns[i] = evn[i];<!-- [et_pb_line_break_holder] --> //test = evns[i];<!-- [et_pb_line_break_holder] --> //alert("evens = " + test );<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> if (middle==0)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> evns.sort(ordervalues);<!-- [et_pb_line_break_holder] --> middle = evns[Math.floor(shown/2)];<!-- [et_pb_line_break_holder] --> //alert("middle = " + middle );<!-- [et_pb_line_break_holder] --> } else {<!-- [et_pb_line_break_holder] --> middle = evn[middle-1];<!-- [et_pb_line_break_holder] --> } <!-- [et_pb_line_break_holder] --> for (i=0; i<shown; i++)<!-- [et_pb_line_break_holder] --> {<!-- [et_pb_line_break_holder] --> evn[i] = evn[i]-middle;<!-- [et_pb_line_break_holder] --> //test = evn[i] ;<!-- [et_pb_line_break_holder] --> //alert("middle = " + middle );<!-- [et_pb_line_break_holder] --> document.getElementById("comev"+i).value = Math.round(evn[i]*100)/100;<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> }<!-- [et_pb_line_break_holder] --> });<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> });<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] -->//-->!]]><!-- [et_pb_line_break_holder] -->function ordervalues(a,b)<!-- [et_pb_line_break_holder] -->{<!-- [et_pb_line_break_holder] -->return a-b;<!-- [et_pb_line_break_holder] -->}<!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --></script><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> <div id="primary"><!-- [et_pb_line_break_holder] --> <div id="content" role="main"><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> <?php the_post(); ?><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> <?php get_template_part( 'content', 'page' ); ?><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> <?php comments_template( '', true ); ?><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> </div><!-- #content --><!-- [et_pb_line_break_holder] --> <!-- HDR Exposure FORM HTML AND PHP PART 2 (MESSAGES) GOES HERE --><!-- [et_pb_line_break_holder] --> <div id="hdrexposure-form"><!-- [et_pb_line_break_holder] --> <!-- [et_pb_line_break_holder] --> <form action="<?php the_permalink(); ?>" id="hdrexposure-form" method="post"><!-- [et_pb_line_break_holder] --> <table><!-- [et_pb_line_break_holder] --> <tbody><!-- [et_pb_line_break_holder] --> <tr> <!-- [et_pb_line_break_holder] --> <th>Shutter Speed</th> <!-- [et_pb_line_break_holder] --> <th>Aperture</th><!-- [et_pb_line_break_holder] --> <th>ISO</th><!-- [et_pb_line_break_holder] --> <th>Computed EV</th><!-- [et_pb_line_break_holder] --> </tr> <!-- [et_pb_line_break_holder] --> <tr><!-- [et_pb_line_break_holder] --> <td><input id="et0" type="text" name="et0" value="0" /></td><!-- [et_pb_line_break_holder] --> <?php if($et0_error != '') { ?><!-- [et_pb_line_break_holder] --> <p class="error"><?php echo $et0_error;?></p><!-- [et_pb_line_break_holder] --> <?php } ?><!-- [et_pb_line_break_holder] --> <td><input id="apr0" type="text" name="apr0" value="0" /></td><!-- [et_pb_line_break_holder] --> <?php if($apr0_error != '') { ?><!-- [et_pb_line_break_holder] --> <p class="error"><?php echo $apr0_error;?></p><!-- [et_pb_line_break_holder] --> <?php } ?><!-- [et_pb_line_break_holder] --> <td><input id="isosen0" type="text" name="isosen0" value="0" /></td><!-- [et_pb_line_break_holder] --> <?php if($isosen0_error != '') { ?><!-- [et_pb_line_break_holder] --> <p class="error"><?php echo $isosen0_error;?></p><!-- [et_pb_line_break_holder] --> <?php } ?><!-- [et_pb_line_break_holder] --> <td><input id="comev0" type="text" name="comev0" readonly="readonly" value="0" /></td><!-- [et_pb_line_break_holder] --> </tr><!-- [et_pb_line_break_holder] --> </tbody> <!-- [et_pb_line_break_holder] --> </table><!-- [et_pb_line_break_holder] --> <table><!-- [et_pb_line_break_holder] --> <tbody><!-- [et_pb_line_break_holder] --> <tr><!-- [et_pb_line_break_holder] --> <td><input id="et1" type="text" name="et1" value="0" /></td><!-- [et_pb_line_break_holder] --> <td><input id="apr1" type="text" name="apr1" value="0" /></td><!-- [et_pb_line_break_holder] --> <td><input id="isosen1" type="text" name="isosen1" value="0" /></td><!-- [et_pb_line_break_holder] --> <td><input id="comev1" type="text" name="comev1" readonly="readonly" value="0" /></td><!-- [et_pb_line_break_holder] --> </tr><!-- [et_pb_line_break_holder] --> </tbody> <!-- [et_pb_line_break_holder] --> </table><!-- [et_pb_line_break_holder] --> <table><!-- [et_pb_line_break_holder] --> <tbody><!-- [et_pb_line_break_holder] --> <tr><!-- [et_pb_line_break_holder] --> <td><input id="et2" type="text" name="et2" value="0" /></td><!-- [et_pb_line_break_holder] --> <td><input id="apr2" type="text" name="apr2" value="0" /></td><!-- [et_pb_line_break_holder] --> <td><input id="isosen2" type="text" name="isosen2" value="0" /></td><!-- [et_pb_line_break_holder] --> <td><input id="comev2" type="text" name="comev2" readonly="readonly" value="0" /></td><!-- [et_pb_line_break_holder] --> </tr><!-- [et_pb_line_break_holder] --> </tbody> <!-- [et_pb_line_break_holder] --> </table><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --> <table><!-- [et_pb_line_break_holder] --> <tr><!-- [et_pb_line_break_holder] --> <td <label for="c_submit"> </label><input type="submit" VALUE="Compute EV" name="c_submit" id="c_submit"/></td><!-- [et_pb_line_break_holder] --> <td><input type="reset" value="Reset to Zero" /></td><!-- [et_pb_line_break_holder] --> </tr><!-- [et_pb_line_break_holder] --> </table><!-- [et_pb_line_break_holder] --> </form> <!-- [et_pb_line_break_holder] --> </div><!-- [et_pb_line_break_holder] --> </div><!-- #primary --><!-- [et_pb_line_break_holder] --><!-- [et_pb_line_break_holder] --><?php get_footer(); ?>

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