First of all, to all those who think that some Polarizer show little effect and are more expensive. A polarizing filter can, and this is true for all price ranges, only at a certain angle to the light source (usually the sun) show its effect. Reflections on glass surfaces and and other reflective surfaces (except metal) can best reduce at an angle of 30 to 40 °. The famous dark blue sky and lush green plants form the largest impact at an angle of 90 ° to the sun. Now for Walimex Polarizer. Blurring or changes in the image quality need not be feared. Here Walimex playing quite in the same class, such as Hoya and Praktica. The light loss of approximately 11/2 aperture is at the level of other brands such as B & W. Where the more expensive filters are better, that's the mechanics. My Walimex hardly could no longer be good screws on the lens, but difficult to turn and after test shots in the garden at about 0 ° temperature. As technically slightly adept Fotofreund but you can help by wrapped the polarizing filter in foil packs for a few hours in the freezer and then, if he has returned to room temperature, very carefully with a needle a little graphite oil into the slot between the surfaces / rings brings. Now the Walimex Polarizer turns lush and soft, like an expensive filter. For the optical power I forgive 5 star and for the mechanics 2-3 star, from which the 4-star result. His money is all worth Polarizer and after modification as well as the more expensive brands reputation.