Tiffen 72mm Wide Angle Circular Polarising Filter (Slim Profile Design) Tiffen 72mm Circular Polarising Filters - Reflected light rays become polarised. Polarising filters are used to select which light rays enter your lens. They can remove unwanted reflections from non-metallic surfaces such as water or glass and also saturate colours by providing better contrast. The effect can be observed through the viewfinder and altered by rotating the filter. The filter factor varies according to the rotation of the filter and its orientation to the sun. If you are outside on a beautiful day - in the mountains or at the beach - and you want to take a stunning photo of a sky filled with clouds or make the water more saturated, then a polariser is the solution. This filter is the best way to bring out clouds, increase or decrease the saturation of the ocean or increase or decrease reflections on water. You can also use this filter when shooting through glass or windows as it will again allow you to increase or decrease reflections. If you are shooting in black and white and want to simulate a threatening storm, try using a red #25 filter. The landscape will take on the appearance of an impending and menacing storm. Along with a UV or Skylight filter, a polarising filter should be part of every photographer's equipment. It can transform an ordinary image into a stunning creative photograph by increasing colour saturation. This filter uses a wide-angle mount (slim profile). To help eliminate vignetting (darkening of the corners), it has no front thread. Note: Circular polarisers are specifically designed for use with autofocus SLR cameras (they will also work without issue on manual systems) - This filter eliminates ultraviolet rays from outdoor shots whilst polarising light to remove reflections and increase colour saturation, without affecting the overall colour balance - Can significantly enhance a blue sky and make clouds more visible - Used optimally at right angles to the sun - Effective with cameras that use beam splitters in the TTL metering path and with AF cameras