Hunting Washington Forum
Community => Photo & Video => Topic started by: gkowen on August 09, 2009, 08:02:50 PM
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The focus profile of their motion detector on the camera when they hang their camera. I have built a few homebrews and its amazing how much more effective the PIR (motion sensing) is when you consider the focusing of the fresnel lens. Has anyone else considered this?
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I have. I built my first homebrew and it has been in the woods for about a week and a half, but when the case is open it doesn't sense motion unless your right there. Do you put anything on the outside of your case to protect the fresnel lense or do you just glue it to the case?
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Also I have a little bit of a shadow in my picture, have you had that problem? I used a w80. I shave the pvc fitting down some more, but I won't know if that solved the problem until I check the cam next weekend.
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The shadowing is from the pvc fitting. Keep shaving until its gone. You can test it quickly at home too. I just glue mine to the case. What most people do not realize is that if you buy the wide angle fresnel lens (the rectangular one) and put it upside down, the camera will only sense motion above the camera (unless you are very very close to camera). There is an up and a down to the wide-angle fresnel lens.
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I focus all my pir lens using a flash light in a dark room. I then find the camera field of view by taking a photo of the wall from 5 feet and measuring the field of view from the photo. I try to match this with the pir field of view. I do this on every different type of camera, normally because some are a bit slower than others. I can get away with a wider pir field of view on the 600 and other cameras that are 2+ second to trigger.
cliff
