The reflected light rays are polarized. Polarizing filters are used to select which light rays enter your camera lens. They can remove unwanted reflections from non-metallic surfaces like water or glass and saturate colors for better contrast. The effect can be seen through the viewfinder and can be altered by rotating the filter. The filter factor varies depending on the rotation of the filter and its orientation to the sun. When you take a walk on a beautiful day – in the mountains or at the beach – and want to capture a wonderful shot of a sky full of clouds or make the water look more saturated, it's best to use a polarizer. This filter is the best way to enhance clouds, increase or decrease ocean saturation, or enhance or reduce water reflections. You can also use this filter when photographing glass or windows, as it can amplify or diminish reflections. If you're shooting in black and white and want to simulate an impending storm, use a red filter. The image will take on the appearance of an approaching, threatening storm. This filter removes ultraviolet light to eliminate haze in outdoor shots and polarizes light to remove reflections and increase color saturation without affecting the overall color balance. It can sharpen blue skies and brighten clouds. It's best used at a right angle to the sun. Effective with cameras that use light splitters in the path of the TTL exposure meter and with AF cameras. The filter can be rotated separately in the front mounting ring and is compatible with Lee 105 mm front mounting rings.