The Hoya 77mm Pro1 Circular Polariser is an excellent device designed to selct which light rays enter your camera lens. Many light rays are reflected by surfaces and become polarised. By selecting which rays enter your lens, the Hoya 77mm Pro1 Circular Polariser allows you to remove unwanted reflections from non-metallic surfaces such as water and glass. The Circular polariser also enables colours to become more saturated and appear clearer with better contrast- a really excellent feature when you want to capture the contrast and saturation between the blues and whites of the sky. All this and more whilst having no effect on the overall colour balance of the shot.