I attached my new circular polarizer filter on my G5's 14-42 kit lens, and noticed that the camera is having trouble focusing. Without the filter my G5 focuses quite well, but with the filter attached it is hunting, having a difficult time locking focus on simple targets. Is this normal for the AF system? I have used circular polarizers on my AF DSLR's without a problem. Is this a particular quirk of the G5?