Maybe this is something that everybody already know and I’m just finding out on my own. Since moving to Florida some 14 years ago polarizing filters are almost a permanent fixture in front of my lenses but seldom found the need to use them indoor. This year while shooting the Gruden QB Camp shows for ESPN I wanted to eliminate some unwanted glare, nothing serious but it bothered the PIA in me. The centerpiece of these shows is a large LCD monitor, that’s where the conversation about football plays takes place. We usually adjust the brightness of the monitor to match the existing lights and exposure, BTW, all our lights are daylight balanced. I realized that as I was rotating the polarized filter the monitors was also changing the brightness to the point that is was going entirely dark without effecting any other part of the scene. I wasn’t about or had the time to find out why back then, the newly found “technique” came handy in controlling the brightness of the monitors without having to go into its menu. We used polarizer filters on all cameras that had the monitor in the shot.

I experimented a bit further about polarizer and LCDs. When I try to view my iPhone or iPad wearing polarizing glasses the screen goes black.

Maybe somebody has a more scientific explanation?