The filter I have is a Hoya UV, doesn't say much else on the case and I don't know what to look for.
On my trip to Antarctica, being the only person who remembered the HDMI cable I was very popular. When another guy with good equipment saw this type of shot he attempted the same, with his CP filter installed (don't know what make). He end up removing the filter because his shots looked washed out. This is the same problem I was getting with the Hoya UV filter.
These are all taken with the Canon 7D, EF-S 10-22 at 10mm, f8, ISO400
Tony