The latest technologies are also being used in lens coating.
SWC (Subwavelength Structure Coating), developed by Canon, is a new type of technology that uses aluminum oxide (Al2O3) as the structural material of the coating in order to align countless wedge-shaped nanostructures only 220 nm high, which is smaller than the wavelength of visible light, on a lens surface. This nano-scale coating provides a smooth transition between the refractive indexes of glass and air, successfully eliminating the boundary between substantially different refractive indexes. Reflected light can be limited to around 0.05%. Furthermore, it has displayed excellent reflection-prevention properties not seen in conventional coating even for light with a particularly large angle of incidence. Currently, SWC is being used in a broad range of lenses, not only wide angle lenses, which have a large curvature factor, but also large-diameter super telephoto lenses, greatly reducing the occurrence of flare and ghosting caused by reflected light near the peripheral area, which had been difficult in the past.