Tech Tuesday: Sigma Gets Serious about Filters

January 5, 2016

By RF Staff

We expect some new photo product news from CES this week (keep your eye out for tech editor Greg Scoblete's coverage!) But while we're waiting....

Sigma's been producing some amazing lenses for the past few years so it's no wonder that they also make lens filters (who knew, right?). But they recently announced a lens filter that's the first of its kind and may signal a new era in lens protection. Constructed from clear ceramic glass, the Sigma WR Ceramic Protector offers a number of impressive attributes.


If you're into numbers and scientific testing methods, the new lens filter offers offers a Vickers hardness number of 700HV. To us non-engineers, that means that it's one tough lens. Apparently, conventional high strength protective filters generally use chemically strengthened glass but only the surface of the filter benefits from this extra protection.

Sigma claims that the new Protector is three times stronger than chemically strengthened glass (and 10x stronger than traditional filters) because the special heat treatment during production of Clear Glass Ceramic "precipitates microrystalline spinel" throughout the glass and not just on the surface.

Bottom line is that, the scratch- and shock-resistant Protector is less likely to shatter from scratches or cracks than other filters. (Check out the video below for visuals and a voiceover explanation.)

The lens filter is also coated to repel water, dust and oil, so it's can handle outdoor shoots and it's easier to wipe off those errant and oily fingerprint and other smudges. And because the WR coating reflects minimal visible light (0.24 percent, according to Sigma), the filter is less likely to produce flare and ghosting. At the very least, this coating should keep those annoyances (unless you're looking for some romantic flare in your photos) to a minimum while allowing for clear and sharp image capture.

Since it's the first filter made of clear ceramic glass, the protector has a certain cool factor that's appealing, especially since it's up to 50 percent thinner and up to 30% lighter than previous Sigma filters. And, if you've ever had a lens (with or without a camera attached) slip through your fingers onto a hard surface, this filter may well provide extra security should it happen again.

The Sigma WR Ceramic Protector will be available (we just don't know when) in a range of sizes, from 67mm to 105mm. Pricing starts at $93 for the 67mm filter.