I'm looking for a circular polarizer.. I've read in several places that they're pretty important to have. I've had my eye on a Tiffen 67mm filter, runs for about $50, but it's not coated and some people claim it causes glare in some situations. I'm not to keen on spending $130 for a polarizer, but the ones that are MC (multi coated) go for at least $80'ish. Is it worth it? Or will the Tiffen work ok for me?