"Can U.V. filters cause chromatic aberrations?" a customer asked me this weekend. I had to admit that I didn't know, but I feel it is possible. A filter is another element added to the front of the lens. If it isn't made perfectly flat or smooth couldn't it cause chromatic aberration? In the camera store we are always selling U.V. filters as protection for lenses. We sell Hoya and B+W. We always offer the better filters first except for the cheaper kit lenses. With film I have never seen any difference in image quality with either brand. Digital SLR's are much more sensitive. Has anyone done a test?