I wanted to grab a polarizer to do some photography through my back window. I didnt want to spend too much but i was planning on getting it in 58mm and use step down rings so it can be used with all my lenses. Amazon Canada is where i would like to buy from online because I have amazon prime. Anyways amazon has these polaroid polarizers for around 17 bucks. I saw the B+W but it was over 100 dollars. Are these Polaroid ones any good? if not what is a cheap alternative that is good?