With the polarizing filter can produce reasonably usable images as long as no light whatsoever is striking the filter: The images are immediately gray and dull. At wide-angle lenses, which therefore have only a very short sun visor, this filter is practically not useful unless one pays meticulous care always stop in the shade. But even under the best conditions of the filter reduces the image quality very much. My prime lens normally produced tack-sharp images. With this filter, it blurs fine detail. Have promised me more. Tested on EOS 350D and Sigma 30mm / F1.4
