Difference between revisions of "Measuring Lens Field of View"

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<nowiki>
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==Question==
  
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<html>
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'''How do I measure the actual field of view or "viewing angle" of my camera?'''
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<br><br>
 
  
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  <form name="l">
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==Answer==
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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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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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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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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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  return result;
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  }
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==Related Products==
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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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*[[XX34A|AirSight Indoor (XX34A)]]
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  }
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*[[XX41A|AirSight Indoor WideEye (XX41A)]]
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function efl(deg) {
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*[[XX51A|AirSight Indoor WideEye P2P (XX51A)]]
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  return (36/2) / Math.tan((deg/2)/180*Math.PI);
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*[[XX36A|AirSight Outdoor (XX36A)]]
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  }
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*[[XX42A|AirSight Outdoor WideEye (XX42A)]]
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function calculate() {
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*[[XX52A|AirSight Outdoor WideEye P2P (XX52A)]]
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  var x1 = 1.0 * document.l.distancefromwall1.value;
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*[[XX39A|AirSight Indoor SD (XX39A)]]
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  var y1 = 1.0 * document.l.walldistance1.value/2;
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*[[XX49A|AirSight Indoor P2P SD (XX49A)]]
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  var x2 = 1.0 * document.l.distancefromwall2.value;
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*[[XX59A|AirSight Indoor WideEye HD SD P2P (XX59A)]]
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  var y2 = 1.0 * document.l.walldistance2.value/2;
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*[[XX40A|AirSight Outdoor PTZ (XX40A)]]
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  var k = (y1*x2 - x1*y2) / (y2-y1);
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*[[XX50A|Airsight Outdoor PTZ HD P2P (XX50A)]]
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  var jj = document.getElementById("kanswer");
 
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  if (jj) {
 
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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>
 
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</td></tr></table>
 
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</body></html>
 
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</nowiki>
 

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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