Nothing new about curved filters. The main rationale was to reduce the difference in refraction between the edges and centre of the filter (lightrays stiking a filter at an acute angle show different exit angles and pass through a thicker layer of glass than lightrays striking at 90 degrees) It is interesting to see that reduction of flare is added to the benefits. I have always wondered why the production of curved filters didn't catch on.
I have UV filter on all my lenses because I want to protect my investments. I only use heliopan ES 77mm because it cost less then the B+W and it has the same quality German glass.
