Circular polarizers, also referred to as polarizing filters, can be used to create circularly polarized light or alternatively to selectively absorb or pass clockwise and counter-clockwise circularly polarized light.
The polarizing filter used with most modern cameras is a circular polarizer. The first stage of the polarizer is a linear filter which filters out light that is linearly polarized in a specific direction. The second stage, for technical reasons related to the auto sensors within the camera, then circularly polarizes the light before it enters the camera.
The polarizing filter has two applications in both color photography and black and white photography: it reduces reflections from some surfaces, and it can darken the sky.
Circular Polarizer Filter (CPL Filter) is a polarizing filter to remove unwanted reflections from non-metallic surfaces such as water and/or glasses.
By the way the size for this one is 52mm as I will use it on my Panasonic LX3.
The glass color is kind of dark color.
Unlike the other filter I use, this one have this rotating mechanism - basically you will use it to get the result that you want.
OK, let's try it on this water surface;
Without CPL filter;
And now I attached the CPL Filter;
And I start to rotate it and adjust it accordingly;
And finally, I can see that thing there clearly - what ever it is....
Again another test on a different spot - without the CPL Filter;
With the CPL Filter;
I also do some testing on scenery photography - without the CPL Filter;
With the CPL Filter attached;
Further adjustment with CPL Filter;
A simple but quite fun and useful tool this is.