In Reply to: Polarised sunnies posted by yram on Monday, 16. April 2012 at 12:40 Bali Time:
You just need to hold up 2 pairs so you are looking at the sky through both pairs. Then twist 1 pair sideways. The lens should turn black (cant see through it).
Basicallty polarisation works by cancelling out sideways light (very bad way of describing it). So they only let through up & dowbn light rays (not sideways ones). This is how they reduce glare.
So if you turn one pair sideways, and one pair normal, it shodul totally cancell out all light.
Also, you can try putting a pair on and looking at a mobile phone. Then turn your head sideways. Most mobile screens are partially polarised and will turn black when you turn your head.
Make sense??
I tried many polarised sunnies and most were NOT polarised at all even though the sellers told me they were. And then pretended to be all confused when I told them they were not.