NiSi 58mm True Color Pro Nano CPL Circular Polarizing Filter | NiSi Optics USA
Amazon.com : High Definition 58mm CPL Circular Polarizing Filter with Multi-Coating for Canon EF 24mm f/2.8 is USM Lens, Canon EF 28mm f/1.8 USM Lens, Canon EF 50mm f/1.4 USM & Canon