RE #15: No. A circular polarizer is a linear polarizer followed by a 1/4-wave retarder plate. The linear polarizer does the polarizing (really it just selectively admits light with a polarization axis aligned with the polarizer and rejects anything else. it doesn't create any polarization). The light after this part is linearly polarized and it is this that can cause problems with meters and AF systems. So, the circ. polarizer puts the 1/4 retarder next which turns the linear polarized light into circularly polarized light which doesn't cause problems in metering and AF.