Landscape photographers use polarizing, neutral density, and graduated filters of all types for effects they would consider pivotal to their work. Meanwhile, however, the Internet has been beating up UV and other clear types of filters, bringing to light that "UV filters protect your lens" is a falsehood. While even the best UV filters might shatter in an impact, Sigma has developed a brand new filter type called the "WR Ceramic Protector," which is actually supposed to absorb, bend with, and mitigate shock from an impact.
Ceramic is a type of crystallized glass that, in this case, is clear and incredibly strong. Its secret is that it can flex or bend further than typical glass can without breaking in order to actually absorb an impact. Sigma claims its formula provides a 10x increase in strength over traditional glass filters and a 300 percent increase over chemically strengthened glass.
While sapphire glass is popular for use on gadget screens and watch covers because of its extremely high resistance to scratching, its rigidity means it breaks much more easily than other types of chemically strengthened glass. But the ceramic glass used in Sigma's latest release promises to provide the perfect balance of scratch and impact resistance in a package 50 percent thinner and 30 percent lighter than previous Sigma filters.
In addition, the "WR" in the product name indicates weather resistance, thanks to a coating on the front of the filter that repels water, dirt, and oil at a cost of only 0.24 percent of light transmittance. For once, this might be the "real" UV filter we've all been promised in the past.
Sigma's WR Ceramic Protector will come in a wide variety of standard filter sizes from 67mm to 105mm, but pricing and availability is not yet available.
Thanks to Patrick Schmitz to pointing us to a different announcement in German that lists prices of €99 to over €300 for the 105mm filter. So it does get pricey. We can usually expect slightly lower figures in USD for this market.