linear polariser ok for autufocus

This is my first post so I though I would throw this one in. I recently lost my 49mm hoya HMC polariser filter and in a rush by mistake purchaced a 49mm Hoya linear polariser. Now ever since I first purchaced a auto focus camera a Pentax SF7 one of the first, I have always been told and have taken it for gospel that one needs a circular polariser for use with auto focus cameras. However when I recieved the linear polariser purchaced through E Bay I realised my mistake but out of curiosity put it on a lens and tried it out. The result was perfect focusing and the same quality results as the lost circular filter. The cost of the new filter was very little I imagine because nobopdy wants linear filters.

I was too tight to buy new circular polarisers (they seem to be unnecessarily expensive)after reading the same sort of stuff on the web, so I continued using my old polarisers from the 1980's.....
Can't say I have ever had a problem using them or noticed any adverse effects on the images either.

And welcome aboard.

Af seems to be okay with Pentax DSLR but the exposure metering is off depending on which angle the filter is it either goes up or down the metering fault.

From the outset Pentax have been very clear in their, albeit hard to source literature, on this matter that they introduced circular polarising filters to address a metering issue with the LX.

Despite the 'received internet wisdom' that linear filters interfere with focusing I have yet to read of one accurate, believable and convincing example.

Your conclusion is spot on.

Welcome aboard!