Re: Rotating polarizing filters

On Tue, 12 Jun 2007 15:02:48 +0200, "toto" <toto@xxxxxxx> wrote:

Hello,
Sorry for my bad english.
I'm looking for information about rotating polarizing filters, same as the
ones used in photography.
I wish to use such filters but I've found different filters giving different
results :
the most commons have a very little polarizing effect;
others are very efficient : in a position the filter is transparent and
after a rotation, it become opaque.
Does it exist different gradation for this filters ?
Thank you for your help (and your comprehension for my "english")


Polarizing filters used for photography come in two different kinds,
one labeled linear, one labeled circular.

The linear ones behave as you expect.

The ones labeled circular have the effect of a linear polarizer on the
side away from the camera, the polarization is converted to circular
on the side towards the camera.

If you hold the circular pol. away from your eye, with the camera side
toward your eye, hold a linear pol. between the circular pol. and your
eye, then rotate either pol filter, you should see no change

If you turn the circular pol. around so that the camera side is away
from your eye, then when you rotate either filter you should see
extinction.

Lots of things to try.
.

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