CPL: Color and contrast enhancement, Slim-CPL Stays Always the Best Partner for Your Camera ! Light rays which are reflected by any surface can become polarised, so polarising filters are used to select which light rays enter your camera lens. CPL allows you to remove unwanted reflections from non-metallic surfaces such as water, glass etc. They also enable colors to become more saturated and appear clearer with better contrast. This effect is often used to increase the contrast and saturation in blue skies and white clouds. Features: - Ultra-thin high quality picture frame, no dark corners of images. - Advanced knurled technology to prevent the hand sliding, easily install or remove. - Can reduce glare and reflections from non-metallic surfaces, give you clear scenic images. - Can increase the saturation of skies and foliage, creating deep, rich scenic images. - Help to reduce the amount of light entering the lens. - Especially useful in reflective or stray light. - 49mm diameter, fits for all the same size of screw lens. - Suitable for all the same size camera lens' diameter, like Canon, Nikon, Sony, Pentax etc.