Here are a couple of pictures using the CP Filter. The first picture is of Ala Moana Beach at 10mm with the Sigma 10-20 and CP filter. the second picture is of Waikiki and Diamond Head at 18mm with the Nikon 18-300 and CP filter. Except for a slight crop to get rid of vignetting on the first picture and resizing both pictures are as shot.
Interesting to note that I saw very few people taking pictures with DSLR cameras this visit to Oahu. I actually felt a little out of place with my great big camera and lenses... More and more people using their cell phones I'm thinking!