Shipping should start next week (end of January). Here is a video of a drop ball test:
Key features of the Sigma WR ceramic protector filter:
Scratch-resistant – Sigma’s Clear Glass Ceramic offers a Vickers hardness number of 700HV. The strength of the Clear Glass Ceramic is much stronger than chemically strengthen glass and is 10 times stronger than conventional filters
Thinner and lighter – This new protector is up to 50 percent thinner and is up to 30% lighter than previous Sigma filters
High transmittance – Clear Glass Ceramic offers very high transmittance, making it ideal for use as optical glass
Water- and oil-repellent coating – The water repellent coating reflects only 0.24 percent of visible light, thereby minimizing flare and ghosting. Its ability to repel both water and oil is also excellent, with water drops bouncing right off, and fingerprints are easily to remove
As with all of Sigma’s lenses, the filter is checked with Sigma’s own Modulation Transfer Function (MTF) measuring system, “A1,” in the company’s factory in Japan.