Sigma has created the world’s first highly shock-resistant and scratch-resistant clear glass ceramic protective filter. It is called the WR Ceramic Protector Filter and it provides serious lens protection.
Chemically strengthened glass is used in conventional high strength protective filters. Only the surface of the glass is strengthened. Clear glass ceramic is made with a special heat treatment that precipitates micro crystals evenly through the lens for consistent strength.
As a result, the WR Ceramic Protector Filter has 10X the strength of a conventional protective filter and 3x the strength of a chemically hardened glass filter.
Optically clear ceramic glass offers extremely high transmittance. The water-repellent (WR) coating reflects only 0.24 percent of visible light, thereby minimizing flare and ghosting. According to the Sigma website, pricing and availability of the WR Ceramic Protector Filter is coming soon.