Hi, This is probably going to end up being the Weird Question of the Day. I got a circular polarization filter for my camera and I am now playing with it, mostly trying to figure out how it works. I am not sure how many of you approach photography the way I do, probably very few, but I will ask anyway. I know what a polarization filter does. I know I can point it at the window at a shallow angle, rotate the filter and suddently WOOSH glare is gone and I can see through the window. This is all great. The question is WHY. Ok, polarization of light is the function describing the amplitude of the incident light wave. It is always at 90 degrees to the direction of propagation. Sunlight is clearly NOT linearly polarized or my polarization filter would be able to filter it all (it would become all black at 90 degree angle with respect to its polarization). If it is polarized in some other way, then I can write this down as two linearly polarized waves at 90 degrees of each other and out of phase by some angle, which may or may not be constant in time. For the sake of simplicity let's assume it's circularly polarized. For circularly polarized wave the phase is constant 90 degrees. Incident light falls upon glass. Narurally some of it is reflected, some is refracted, depending on the refractive index of the glass. I have seen the math behind it and I simply CAN'T remember EVER seeing refraction or reflection ever depending on the polarization function of the wave!!! According to my calculation both circularly and eliptically polarized light always reflects rotating the other way. Both of my linearly-polarized wave functions are reflected equally. Needless to say that means that no polarization filter has any chance of filtering out reflections. BUT IT DOES, so I must be wrong. I Googled the answer and I found that horizontally polarized waves reflect better at shallow angles. I never found out why, though. So now I have polarization of reflected light dependending on angle of incidence and I don't remember ever seeing this stuff when playing with Maxwell's equations. Any ideas? What am I missing?