Linear or Circular Polarizing filter?

[kartwheel]

Hi All,
I have a Panasonic LX3, and I've bought a 52mm extension tube so that I can attach filters, (havn't received it yet).

I have an old jessops circular polarizing filter - probably about 15 years old, which I could use, but I was thinking about buying new as I thought the quality of filters may have improved by now?
Anyway, I've done a bit of research and found that my camera will work with the linear type of filter, and advice appears to be that the linears are much better value for money than the circulars.
I want to spend around £20, and I've been searching online.

Ive seen a Kenko circular polarizer for £16.50 incl. delivery, which I think is a very good price as it is actually a Japanese Hoya, and seems to retail elsewhere at around £28.
But, I can't find many linear polarizers under £20. Hoya sells them for £29, and Ive come across a Kood linear filter for £16 incl. delivery. ( Allthough I've had to email the seller of the Kood to check that it will work as the website states that this filter will not work with autofocus cameras. - I think they've put this just because it won't work with most DSLRs )

Anyway, (assuming the linear will work fine,) my question is which should I buy?
Will the linear Kood give better quality results than the circular Kenko?
Or should I stick with my old Jessops?

I'll be most greatfull for anyones thoughts / opinions.

[OrbitalPete]

My understanding is that linear polarising is better, but the metering and autofocus systems in most cameras mean you need a circular polariser for them to work correctly.

[SomeVorn]

I think I'm going to have to burst your bubble. Digital sensors require circular polarising filters in order to meter correctly. I may be wrong but when i bought my first one years ago, that was certainly the advice given to me by the lady behind the counter.

[OrbitalPete]

I believe it's the mirrors used rather than the sensor; sensors shouldn't care about polarisation, but mirrors (maybe it's prisms?) can behave oddly iirc. The same problem effected film I believe (but it's been a while and I may be wrong...)

[shotokan101]

FWIW WP has some useful background info....

Photographic filter - Wikipedia, the free encyclopedia

Jim

[kartwheel]

It's my understandig that unlike most DSLRs, the Lx3 doesn't use a beam splitter for the auto focus , so a linear polarizer is OK.

[shotokan101]

Originally Posted by kartwheel

It's my understandig that unlike most DSLRs, the Lx3 doesn't use a beam splitter for the auto focus , so a linear polarizer is OK.

May be true but most posts seem to indicate that you won't see a noticeable quality hit with a circular......

Jim