because they are - except for the polarizing filter - resin. I did not expect, but consistently optical glass. But of course, Polaroid has not not say in the article description, they were made of glass. I only can not imagine otherwise me. But after the initial shock I suppose the filter benevolent in use. After all, why should synthetic resin be worse than glass? At least the filter are easily pleased. And I remember at the company Cokin, which sold a rather expensive and creative range of filters - all synthetic resin! And no one has time bitching about blurring. In addition, the Polaroid filters are multicoated-remunerated. I let the filters so their chance and expect them to behave the way I was used to from glass filters it.
