How does a circular polarizer filter work?

Question

On a camera...

Answer 1

This is mostly analogy but think of a pl filter as a sheet of opaque material having little tiny slots cut in it. The only light that can be seen is the light that passes straight through, not light that enters at an angle. as you turn it, the slots line up differently and give different lighting effects. This is normal polarizing. It can mess up autofocus in some digital cameras.

Now instead think of a little tiny series of round holes drilled through the material. same effect, only light entering directly gets through, but now turning it makes no difference because the holes are round. This is a circular polarizing filter.

I hope my analogy was clear enough.