In order to talk about a circular polarizer, you have to understand its purpose, what it works with.
Lets start with light. Light has many sources, could be the sun, a light bulb, or maybe even a reflection. Light travels out or emanates from its source. It radiates or travels out in a wave; it flows out randomly and in all directions. Light can be reflected, like off of a wall, glass, metal or even off of water. Imagine light traveling horizontally and vertically also in circular patterns clockwise and counterclockwise. By this I mean the light is almost on several different planes.
In photography, trying to capture a picture or image light is always present, in some form. You may or may not be happy with how the light is falling on your vantage point. It may be necessary to filter out the light to intensify work, it maybe necessary for clarity of an object. Your goal may be to enhance the color. It may be a goal to project more depth in an image. To do this, you would have to be able to control the pattern of light. Well thats exactly what a circular polarizer does. The word filter comes to mind. Allowing certain things in or keeping certain things out. In our case, it is light. With the circular polarizer, I am able to capture the light traveling in a certain pattern or it may even be thought of as having the abillity to block scattered light or atleast to be able to adjust it like a beam to make my enhancements. With the circular polarizer, I am in control of the tool in my arsenal to get the results that I need, feeling confident that I have achieved my goal in creating my perfect shot.
If youre into photography you may want to invest in a polarizer filter for your camera. These are especially useful if you like to do landscape photography. A polarizer filter can make colors much richer and deeper. Sometimes in nature colors are naturally uneven when photographed, which makes it hard to really capture the beauty of something you see. With the use of the filter this problem can be eliminated. Colors will be evened out and rich. The sky will appear blue all the way across and the leaves on trees can go from a mottled green shade to a deep, beautiful hue. These filters can also do away with reflections when photographing water.
There are lots of different kinds of polarizing filters for sale, so the process of purchasing one can be overwhelming if youve never bought one before. The kind you buy will depend on your camera and your lens type. You can get the kind that screw onto your lens or the kind that is made to fit a particular lens size. Keep in mind that if you have a cheaper lens on your camera you may have a hard time finding a polarizing filter thats a good fit.
When you look through your camera for the first time with the filter in place everything will probably seem too dark. This is normal. Your eyes will get used to the effect, just give it time. Dont move the filter around too quickly in an attempt to make things seem brighter. Its best to move it slowly so that your eyes can pick out the different contrasts in the colors. Youll love the effect the polarizing filter has, and it will make taking landscape photographs much more enjoyable for you.