Sigma 82mm WR Circular Polarizer Filter: Specifically designed for use with most of the auto focuses SLR cameras and lens. The Sigma filter is an essential accessory for outdoor photography and fits to selected lenses with a 82mm filter thread. This filter removes unwanted reflections from non-metallic surfaces such as water or glass and also saturates colors providing better contrast. The polarizer helps make a blue sky more bluer as well as making clouds stand out. The effect can be seen through the viewfinder and changed by rotating the filter. It produces strongest effect when used at a 90į angle from the sun. This Sigma WR Circular Polarizer Filter is coated to repel water drops and resist smudging from fingerprints. It is also treated to exhibit anti static properties to prevent microscopic dust from clinging to the front surface. This helps to ensure sharp images. The filter increases light transmission and colour saturation without affecting the overall colour balance. It clears up haze in distant landscapes and provides more saturated & vivid colours. The filter protect front lens surface from dust, scratches, dirt and fingerprints. The filter is lightweight and very easy to install & detach from lens.