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Old March 28th, 2007, 09:35 AM   #1
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diffraction? Using nd filters

Hey,

I've heard some people say to use an ND filter on a camcorder to avoid difraction (using the narrow f stops?) I just picked up a ND6 for my GS400 and now in day light, my auto exposure reads 6.8, and at 5.6 depending on the light. I've been told to shoot in these apertures to get the sweet spot of the lens. Do I have my information right? I know there's automatic ND filters also in my cam, but I don;t know when they kick in.
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Old March 29th, 2007, 12:36 PM   #2
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HD cameras with 1/3" chips are at the diffraction limit at about f/8 thus sharper pictures (though with less depth of field) will be obtained by using wider (smaller f number) apertures. A neutral density filter requires a larger aperture, ceteris paribus, to make up for the light lost to the filter. Thus a neutral density filter is one way to stay away from the diffraction limited lens apertures. Another is to reduce the exposure time (increase shutter speed).
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Old April 3rd, 2007, 04:25 AM   #3
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"I know there's automatic ND filters also in my cam, but I don;t know when they kick in."

I really doubt your camera has something like automatic ND filters. If your camera has ND filters then you have a switch or a filter wheel. You can clearly see a filter being put in front of the chip, this can't be an automatic process or it'd ruin your shots
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Old April 3rd, 2007, 07:17 AM   #4
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Forgot to mention it: If your camera throws in ND filters automatically it should tell you that it has done this by giving an indication in the view finder AND you should be able to turn this feature off. If hazy recall is correct the Canon XL1 worked that way.
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