I was messing around with my polarizing filter today because I found out that the light from most LCD monitors is polarized.
If you don’t know what a polarizing filter does, basically its a dark piece of glass, that can be used to block out polarized light, such as reflections from windows. These are great tools for a photographer.
For example, want to take a picture of a car without getting a reflection of lots of junk, want to take a picture through a window at the zoo, want to get more contrast in the sky, put on the polarizing filter. Rotate it so it points at the light source.
So in this image my hand is on the LCD screen and the filter has been rotated to block the light from the screen. However the 2nd reflection of the white light of my hand gives it the halo effect.
Its useful in an abstract sense, but might be harder to use in a real world shot, interesting to play with though.