Suzie wrote to me to ask "I have a question. I am in the market for a circular polarizer filter and was wondering if you could recommend a good brand. The one filter I do have (UV) is a Tiffen and it seems to work fine, but it was kind of pricey - though I do realize good quality glass is important."
Here's my response to her...
Unfortunately the only real answer is; the more you spend, the happier you'll be. I bought one that was kinda cheap at about $80.00 (which I don't really consider cheap) , it's an off brand called "Omega" and it's 77mm for my Canon L series lenses. I HATE IT! I should have spent the $144.00 and bought the B+W brand (or $200.00 for the B+W with 81A warming filter).
Whenever I use the Omega filter (which is never anymore) I would almost always get photos that looked at least very soft, and at worse out of focus and unusable. Also I think the filter lost me about 2-3 f/stops ... B+W claims theirs is about 1.3 stops.
So ... to make a long story even longer, just figure out what you can afford and find the one closest to your price point. I think for the most part with camera accessories you get what you pay for.
For anyone reading this wondering what a polarizer is for, have a look at the photo below.
A polarizer will reduce glare, satrurate colors (especially sky) and it also reduces reflection off water which can be real handy when trying to photograph fish in shallow water.