Difference between revisions of "Measuring Lens Field of View"

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Here is a script that does all of that computation for you:
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==Question==
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<br><br>
 
  
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  <form name="l">
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'''How do I measure the actual field of view or "viewing angle" of my camera?'''
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  <blockquote><table border=0 cellpadding=1 cellspacing=0 bgcolor="#C0C0C0"><tr><td><table border=0 cellpadding=4 cellspacing=0 bgcolor="#F8F8F8"><tr><td>
 
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  <table><tr><td>
 
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  <table>
 
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  <tr><td align=right><b>Near Distance From Wall</b></td><td><input name="distancefromwall1" type="text" size=10></td></tr>
 
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  <tr><td align=right><b>Near Wall Distance</b></td><td><input name="walldistance1" type="text" size=10></td></tr>
 
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  <tr><td align=right><b>Far Distance From Wall</b></td><td><input name="distancefromwall2" type="text" size=10></td></tr>
 
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  <tr><td align=right><b>Far Wall Distance</b></td><td><input name="walldistance2" type="text" size=10></td></tr>
 
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  </table>
 
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  </td><td>&nbsp;</td><td>
 
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  <input type="button" value="Calculate Answer" onClick="javascript:calculate()"><br>
 
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  <br>
 
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  Near FOV&deg; = <span id="fovest1"></span><br>
 
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  Far FOV&deg; = <span id="fovest2"></span><br>
 
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  k = <span id="kanswer"></span><br>
 
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  Final FOV&deg; = <span id="fovanswer"></span><br>
 
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  Effective focal length = <span id="angularfocallength"></span><br>
 
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  </td></tr></table>
 
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  </td></tr></table></td></tr></table></blockquote>
 
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  </form>
 
  
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<script>
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==Answer==
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function roundNumber(num,dec) {
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  var result = Math.round(num*Math.pow(10,dec))/Math.pow(10,dec);
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If you are unsure about the actual field of view for your camera you can calculate the angle using the calculator found '''[http://panohelp.com/lensfov.html here]'''.
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  return result;
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  }
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We currently carry three different size lenses. The sizes and other specifications can be found on our '''[[AirSight_Comparison_Chart | Airsight Comparison Chart]]'''.
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function ffov(y,x) {
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  return (2*Math.atan(y/x)) * 180/Math.PI;
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==Related Products==
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  }
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function efl(deg) {
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*[[XX34A|AirSight Indoor (XX34A)]]
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  return (36/2) / Math.tan((deg/2)/180*Math.PI);
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*[[XX41A|AirSight Indoor WideEye (XX41A)]]
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  }
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*[[XX51A|AirSight Indoor WideEye P2P (XX51A)]]
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function calculate() {
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*[[XX36A|AirSight Outdoor (XX36A)]]
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  var x1 = 1.0 * document.l.distancefromwall1.value;
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*[[XX42A|AirSight Outdoor WideEye (XX42A)]]
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  var y1 = 1.0 * document.l.walldistance1.value/2;
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*[[XX52A|AirSight Outdoor WideEye P2P (XX52A)]]
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  var x2 = 1.0 * document.l.distancefromwall2.value;
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*[[XX39A|AirSight Indoor SD (XX39A)]]
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  var y2 = 1.0 * document.l.walldistance2.value/2;
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*[[XX49A|AirSight Indoor P2P SD (XX49A)]]
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  var k = (y1*x2 - x1*y2) / (y2-y1);
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*[[XX59A|AirSight Indoor WideEye HD SD P2P (XX59A)]]
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  var jj = document.getElementById("kanswer");
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*[[XX40A|AirSight Outdoor PTZ (XX40A)]]
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  if (jj) {
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*[[XX50A|Airsight Outdoor PTZ HD P2P (XX50A)]]
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    jj.innerHTML = roundNumber(k,3);
 
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    }
 
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  var fov = ffov(y1,x1);
 
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  jj = document.getElementById("fovest1");
 
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  if (jj) {
 
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    jj.innerHTML = roundNumber(fov,2)+"&deg;";
 
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    }
 
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  var fov = ffov(y2,x2);
 
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  jj = document.getElementById("fovest2");
 
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  if (jj) {
 
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    jj.innerHTML = roundNumber(fov,2)+"&deg;";
 
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    }
 
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  fov = ffov(y1,(x1+k));
 
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  jj = document.getElementById("fovanswer");
 
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  if (jj) {
 
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    jj.innerHTML = "<b>"+roundNumber(fov,2)+"&deg;</b>";
 
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    }
 
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  jj = document.getElementById("angularfocallength");
 
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  if (jj) {
 
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    jj.innerHTML = "<b>"+roundNumber(efl(fov),2)+"</b>";
 
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    }
 
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  }
 
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function lenstest1() {
 
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  document.l.distancefromwall1.value  = "29.125";
 
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  document.l.walldistance1.value      = "39.84375";
 
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  document.l.distancefromwall2.value  = "68";
 
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  document.l.walldistance2.value      = "91.375";
 
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  calculate();
 
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  }
 
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function lenstest2() {
 
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  document.l.distancefromwall1.value  = "36";
 
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  document.l.walldistance1.value      = "49.625";
 
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  document.l.distancefromwall2.value  = "107.4375";
 
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  document.l.walldistance2.value      = "145.375";
 
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  calculate();
 
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  }
 
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function lenstest3() {
 
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  document.l.distancefromwall1.value  = "34";
 
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  document.l.walldistance1.value      = "48.125";
 
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  document.l.distancefromwall2.value  = "77.5625";
 
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  document.l.walldistance2.value      = "107.0625";
 
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  calculate();
 
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  }
 
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function lenstest4() {
 
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  document.l.distancefromwall1.value  = "30.875";
 
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  document.l.walldistance1.value      = "42.25";
 
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  document.l.distancefromwall2.value  = "74.125";
 
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  document.l.walldistance2.value      = "100.125";
 
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  calculate();
 
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  }
 
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function lenstest5() {
 
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  // 700_1219, 700_1220
 
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  document.l.distancefromwall1.value  = "18";
 
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  document.l.walldistance1.value      = "4.08";
 
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  document.l.distancefromwall2.value  = "30";
 
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  document.l.walldistance2.value      = "7.0162";
 
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  calculate();
 
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  }
 
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</script>
 

Latest revision as of 19:48, 20 May 2014

Question

How do I measure the actual field of view or "viewing angle" of my camera?

Answer

If you are unsure about the actual field of view for your camera you can calculate the angle using the calculator found here.

We currently carry three different size lenses. The sizes and other specifications can be found on our Airsight Comparison Chart.

Related Products

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