Circular Polarizing Filters Are Made For All Cameras With Beam Splitters In The Light Paths Of Their Ttl Exposure Meter And With Autofocus Lenses. Circular Polarization Has The Same Pictorial Effect As Linear Polarization, But Allows For Proper Exposure Metering And/Or Autofocus Distance Settings. - Features:The “High-End” Polarizing Foils Of The Käsemann-Type Filters Are Neutral In Color. - They Have A Higher Efficiency Than Conventional Polarizing Foils And They Are Cemented Between High-Grade Plano-Parallel Optical Glass. The Resulting Sandwich Is Then Precision-Polished Again To Achieve Highly Accurate Plano-Parallel Surfaces.