What is the correct circular polarizing filter?

[2_Rastas]

Hello, I'm using a Canon 28 - 135 IS USM lens and I'm looking for a circular polorizing filter. I'm told that not all circular polarizing filters are created equal. Can anybody help a guy out?

Thanks in advance for any help

2_Rastas

[Bob Atkins]

You need a good quality 72mm circular polarizer. I'r recommend a Hoya or Tiffen as being good value and good quality.

If you can afford it, I'd get the Hoya 72mm HMC circular polarizer.  The HMC (Hoya Multi-Coated) filters are very good and the coating can suppress flare under adverse lighting conditions. If that's too expensive, uncoated Tiffen 72mmm circular polarizer is pretty good (I have one myself)