CPL:Color and contrast enhancement: 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: Slim Circular Polarizing Filter, no dark corners of images Removes unwanted reflections from non-metallic surfaces such as water or glass and glare from the sun Increases color saturation, creating deep, rich scenic images Helps to reduce the amount of light entering the lens Especially useful in reflective or stray light 77mm 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.             Size: 77mm Type: CPL Filter   Package weight: 0.106 kg Product size (L x W x H): 7.9 x 7.9 x 0.8 cm / 3.10 x 3.10 x 0.31 inches Package size (L x W x H): 9.6 x 9.6 x 1.7 cm / 3.77 x 3.77 x 0.67 inches Package contents: 1 x 77mm CPL Filter Lens for Nikon Canon Sony DSLR Camera, 1 x Plastic Case