There are a number of tools photographers use to improve their photos, one of the more important tools being the Polarizing filter. Similar to polarized glasses, Polarizing filters cut glare and enrich colors when used correctly. To be fully effective, polarizing filters must be used at an approximate 90 degree angle from the sun, otherwise the polarizing effect isn't as noticeable. These filters allow you cut the sun's glare from water, rocks, and vegetation. They also give you deeper and richer colors, especially in the sky. Polarizing filters generally come in two forms, Circular and Rectangle/Square. Circular Polarizers (CP) are the most common and easier to use variety, and simply screw on to the end of your lens with the correct filter size (52mm, 77mm, etc). Once attached, the polarizing element is rotated on the filter until the polarizing effect can be noticed through the camera's viewfinder. As with most filters, it pays to invest a bit more money in a quality filter than to buy a lower quality product that will result in lower quality photos. I never leave home without my CPs!