Lee Linear Polarizer filter doesn't polarize?

[B Griggs]

I recently took photos using a glass Lee Linear Polarizing filter, and it does n ot appear to have worked-- prints revealed reflections in windows, which is not supposed to happen with a polarizer. Nor was the sky appreciably darkened, even though I was nearly at a 90 degree angle from the sun. I flipped the filter and rotated it, and took several tests. Nothing happened. What gives? Thanks for the help.

[Bruce Wehman]

Burke, Polarizing filters will lessen such reflections, not eliminate them. All you can hope for is to maximize the effect. Simply hold the filter up to your eye, rotate it to find the darkest position, take your meter reading through it and transfer it to your camera without changing the rotation. I usually put a pencil mark on the ring to mark the top of the position.

[Bill C]

Burke, actually a polarizing filter is "supposed to" eliminate reflections in glass only at a specific angle. If, for example, you look directly into a piece of glass (ie, a window, etc) such that you see your own reflection, the polarizing filter will NOT stop it. Likewise, if you get close to the glass and look off at a shallow glancing reflection, again the polarizer will fail to block it.

However, if you look at the glass at an angle of about 57 to 58 degrees (where perpendicular is 90 deg) you should find that your polarizer can block reflections almost perfectly!

In case you don't understand that angle clearly, if you were 5 feet from the glass and looking directly at it, there is a place on the glass about 1.5 times that (ie, 7 or 8 feet) to the side where the reflection can be almost totally blocked by the polarizer (assuming polarizer is properly rotated).

If you look at any photo where a polarizer blocks glass reflections, I think you'll find that the glass is (nearly) always at this angle to the camera. The same situation exists for other reflective objects (including water but no metals), except that the angle is not exactly the same. But now, having an idea how it works, you can reposition yourself by trial and error to get the optimum effect. This is really a characteristic of light and reflections rather than a failing of your filter. Unfortunately it's frequently not understood by photographers; maybe this will put you a step ahead. (PS, look up Brewster's angle if you want to find more info.)

[Bill C]

>> However, if you look at the glass at an angle of about 57 to 58 degrees (where perpendicular is 90 deg) you should find that your polarizer can block reflections almost perfectly! <<

Whoops! I think I messed up on that one. This should be 57 to 58 degrees OFF PERPENDICULAR. The example distances were ok, though!