Which Circular Polorizor?

[swan]

Hi all, i am looking to buy a circluar polorizor but im not sure which to get. I have the satnderd cannon kit lens and a cnon 50 mm 1.8. I also have the Cokin P system, any suggestions?

[Jon]

58 mm circular polarizer (no need to get the Thin, or the Kaesemann variants) and a 52-58 mm step-up ring. My personal preference would be the B+W MRC; Heliopan SH-PMC or Hoya S-HMC are also good. The Cokin assembly would just be so bulky on those two lenses that I wouldn't want to use it for a polarizer, which gets used a lot. The 52-58 step-up ring will let you use the same filter on both lenses. You don't want to get a 52 mm filter and 58-52 step-down, though.

[jonnypb]

I've got a hoya circular polorizor for my sigma 17-70. One question though when it's screwed on the end spins round like a manual focus ring and it has a small white marking on the ring that turns round which i presume is for something but i don't know what. I've turned the ring round but i can't see any difference??

[Jon]

Try looking at a stream, or a reflection in a window while you turn it. You'll see the reflections come and go. Then point the camera at right angles to the sun and spin it again; you should see the blue of the sky change in intensity. The index mark's for use with cameras that don't have a TTL viewing mode; you'd turn the filter until you saw max. effect and then ttach it to the lens and re-orient the index marker.