PRODUCT HIGHLIGHTS - Filter factor of 1.25 to 1.4x - +0.3 to 0.5 stops - Helps eliminate reflections and glare - Reduces haze in landscapes - Better colour saturation and tonality - Multi-coated optical glass with black mount - Water, oil, static, and scratch resistant - Thin aluminium alloy filter ring - 49 mm front filter thread - Knurled front edge, plastic case Introduction to the Sigma AFM9C0 Sigma's 49 mm WR (Water Repellent) Circular Polarising Filter helps reduce reflections and glare by filtering light that has been polarised by reflection off a non-metallic surface. Sunlight naturally becomes partially polarised when it reflects off the electrons in air molecules, causing light to scatter in the form of haze. A polarising filter organises and filters this polarised light in a directional manner perpendicular to the reflected light, allowing a large portion of this light to be absorbed. The result is a notable reduction in reflections and glare on non-metallic surfaces as well as an increase in the saturation of skies and foliage. A circular polariser differs from a linear polariser only in that it contains a quarter-wave plate in addition to the linear polarising filter. The addition of this quarter-wave plate allows linearly polarised light to be circularly polarised for use with autofocus and exposure functions. Due to the way light is broken down and filtered with a linear polariser, the accuracy of autofocus and exposure is impaired during use. When light becomes circularly polarised, it allows these functions to be used. This filter is multi-coated to eliminate ghosting and internal reflections. An anti-static coating helps limit the build-up of static electricity, making it easier to remove dust particles or preventing them from adhering to the filter. In addition, a water-repellent coating improves beading on contact with water, as well as oil, for greater cleaning efficiency while improving scratch resistance. Sigma's WR Circular Polarising Filters are made from optical glass with a black mount. Mounted in an aluminium alloy filter ring that can be rotated to adjust the intensity of the polarising effect, the glass offers increased clarity and colour fidelity, while the black mount further ensures that no reflections occur along the edge of the filter. - Helps reduce reflections and glare by filtering light that has been polarised by reflection off a non-metallic surface. - Polarising filters organise and filter polarised light in a directional manner perpendicular to the reflected light, allowing a large portion of the light to be absorbed. - Eliminates haze in distant landscapes and provides more saturated and vibrant colours. - Maximum effect when used at a 90° angle to the sun. - Circular polarisers are ideal for use with digital cameras and autofocus lenses where a linear polariser often disrupts exposure and autofocus functions. - Multi-coated to help eliminate ghosting and internal reflections. - An anti-static coating helps limit the build-up of static electricity, making it easier to remove dust particles or preventing them from adhering to the filter. - A water-repellent coating improves beading on contact with water, as well as oil, for greater cleaning efficiency while improving scratch resistance. - The filter factor of 1.25 to 1.4x reduces exposure by 0.3 to 0.5 stops. - Made from clear optical glass with a black mount that further ensures no reflections occur along the edge of the filter. - The thin aluminium alloy filter ring helps prevent vignetting and is durable while remaining lightweight. - The filter ring can be rotated to adjust the intensity of the polarising effect. - Knurled front edges provide a textured grip when mounting or removing the filter from a lens. - The 49 mm front thread allows use with other filters. - Plastic filter case for storage and transport.