Sigma WR Ceramic Protector

Sigma has developed innovative filters for lens front elements that meet the company's high quality standards and help photographers make the most of the lenses they have invested significant time, experience, and money into over the years. In creating the new protective filter for lens front elements, Sigma collaborated with a glass manufacturer for the first time to produce a new type of glass, clear glass-ceramic. The Sigma WR Ceramic Protector made from this advanced material is an extremely reliable filter with outstanding protective features.

Glass-ceramic is an extremely durable, crystallized glass that serves as the basis for clear glass-ceramic and is widely used in aerospace and other industries. This advanced new material combines greater hardness than chemically tempered glass with higher flexibility than sapphire crystal glass, while maintaining the high light transmittance required for optical devices. These properties make clear glass-ceramic the ideal material for lens protection filters.

The chemically tempered glass used for conventional high-strength protective filters is only hardened on the surface through chemical processes. In contrast, clear glass-ceramic is produced using a special heat treatment that ensures uniform filling with the mineral spinel, giving the entire filter consistent hardness. Clear glass-ceramic is the ideal material for protective filters due to its combination of greater hardness than chemically tempered glass and higher flexibility than sapphire crystal glass. It is also shatter-resistant, even in the event of small scratches or chips. Since the risk of shattering into small fragments is reduced, it offers a higher level of safety.