Quote Originally Posted by Steve Smith View Post
I can't see how the polarising part of a circular polariser can be any less effective than a standard linear polariser (because that's what it is). However, it might be possible that the re-circulificating* bit is somehow reducing the contrast a slightly making people think it's less effective at polarising.

(* I can't think of the right word).

You may have hit it. It could be the contrast difference.