A definition of SubWavelength structure Coating (SWC)

A lens coating developed by Canon, and currently employed in its more expensive wideangle optics. The coating consists of wedge shaped structures similar in scale to the wavelength of visible light, which continuously change the refractive index of the light entering the lens. This, Canon claims, helps more light to pass through to the sensor, and less to be reflected where it could be responsible for flare and ghosting.