For many years I have good experience with HOYA filters. This Circular Polarizer is for my new Tamron f2.8 / 70-200mm and would not need to be slim design. But I had with this filter thread found in the coming into question for me lens selection are other copies, so I decided, better Slim as bad ... The filter is transparent, perfectly suited for travel and easy to handle in a robust plastic box with padding insert, lid. Thread smoothly and good rotation of the two discs. Beautifully controlled intensification of sky blue, slowdown of reflexes and increase the color contrast without significant darkening. (My older Polarizer looked blacker out, this clear light gray.) No loss of sharpness in the image result. Just a pity that you can use polarizing filter only without lens hood. In my Pentax-time, I once had an original Pentax lens with an aperture-Geli who possessed a small flap at the bottom, through which one could well reach the knurled ring of the polarizing filter. Unfortunately, this little invention has not been successful ...
