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Old Feb 1, 2008, 4:59 PM   #11
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TCav wrote:
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While Neutral Density filters reduce the intensity of all light, Polarizing filters only reduce the intensity of very bright light.
...
Not true. The reduction of intensity by a polarizing filter has nothing whatsoever to do with the brightness of the light. In theory, it would give the same effect if the light were arriving at the rate of one photon per century.
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Old Feb 1, 2008, 5:54 PM   #12
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BillDrew wrote:
Quote:
TCav wrote:
Quote:
...
While Neutral Density filters reduce the intensity of all light, Polarizing filters only reduce the intensity of very bright light.
...
Not true. The reduction of intensity by a polarizing filter has nothing whatsoever to do with the brightness of the light. In theory, it would give the same effect if the light were arriving at the rate of one photon per century.
Ok, let me try this:

While Neutral Density filters reduce the intensity of all light, Polarizing filters only reduce the intensity of haze, glare, and other forms of reflected light.
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Old Feb 1, 2008, 7:33 PM   #13
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TCav wrote:
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While Neutral Density filters reduce the intensity of all light, Polarizing filters only reduce the intensity of haze, glare, and other forms of reflected light.
Polarizing filters (PF) do in part act as neutral density filters. They preferentially absorb light depending on how it is polarized. "Non polarized" light simply means a random polarization so the PF will absorb roughly half the light - discounting other absorbtion effects in the filter.

It does not depend on how the light became polarized. It could be from some kinds of reflection, absorbtion, or things like a magntic field applied to the light source.

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Old Feb 1, 2008, 8:08 PM   #14
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BillDrew wrote:
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TCav wrote:
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While Neutral Density filters reduce the intensity of all light, Polarizing filters only reduce the intensity of haze, glare, and other forms of reflected light.
Polarizing filters (PF) do in part act as neutral density filters. They preferentially absorb light depending on how it is polarized. "Non polarized" light simply means a random polarization so the PF will absorb roughly half the light - discounting other absorbtion effects in the filter.

It does not depend on how the light became polarized. It could be from some kinds of reflection, absorbtion, or things like a magntic field applied to the light source.
How about this:

While Neutral Density filters reduce the intensity of all light, Polarizing filters reduce the intensity of some light but not other light.
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Old Feb 3, 2008, 10:36 AM   #15
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Polarizing filters reduce the intensity of ALL light but certain light more than others depending on the angle of polarization.
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