Tiffen 105 mm Warm Circular Polariser in water-white glass. This is an outstanding filter designed to bring so much more "punch" to your images. If a traditional polariser isn't giving you enough "oomph", the "Ultra" polariser provides you with a little more. It will further enhance your blue skies – making the difference between a good photograph and an outstanding image. The additional warmth this filter generates comes from incorporating Tiffen's exclusive 812 warming filter. Reflected light rays become polarised. Polarising filters are used to select which light rays enter your camera lens. They can remove unwanted reflections from non-metallic surfaces such as water or glass and also saturate colours, providing better contrast. The effect can be seen through the viewfinder and changed by rotating the filter. The filter factor varies according to the filter's rotation and its orientation in relation to the sun. Note: Circular polarisers are specifically designed for use with autofocus SLR cameras (they will also work without problems on manual systems and video cameras). - Your deep blue sky will become even "bluer" - A highly efficient design - Adds warmth to the image - Made from water-white glass