The Tiffen Warm Linear Polarising Filter is a unique filter combining two Tiffen filters - a polarising filter and an 812 warming filter. Reflected light rays become polarised. Polarising filters are used to select which light rays enter your camera lens. They can eliminate unwanted reflections from non-metallic surfaces such as water or glass and also saturate colours, providing better contrast. The effect can be visualised through the viewfinder and modified by rotating the filter. The filter factor varies depending on the rotation of the filter and its orientation to the sun. A Tiffen 812 warming filter gives you a warming effect that enhances skin tones. Note: Linear polarisers are used with most video cameras and manual focus cameras. They are not recommended for autofocus reflex cameras. Features: - This filter eliminates ultraviolet rays to remove haze from outdoor shots whilst polarising light to eliminate reflections and increase colour saturation, without affecting the overall colour balance - Incorporates the effect of Tiffen's exclusive 812 warming filter, which enhances skin tones and is ideal for portraits taken in cloudy weather or outdoors in the shade on sunny days. Specifications: - Type: Warm linear polariser - Size: 4 x 4" - Filter factor: Between 2.3 and 2.8 (approximately +1.3 stop) - Effect: Eliminates reflections; Increases colour saturation; Adds warmth to pale and washed-out skin tones - Application: Portraits, Nature, Travel, Outdoor photography - Construction: Glass