I bought a polarizer from eBay and it arrived yesterday. It's simply labelled Tiffen Polarizer 52mm on the rim. I attached it to my 12-50mm but turning it seems to not produce any effects in viewfinder or LCD.

Did I get a linear polarizer? Am I right that these may only work on a film camera? How can I tell if my filter is a linear or circular polarizer?

No, both linear and circular polarizers will work on m43 cameras. The problem w/ linear polarizers is that they can mess with the auto focus of DSLRs, but are perfectly fine for mirrorless cameras.

Hi,

Your polarizer is not a dud ...

In my experience with the E-M5 and polarizers, the live-view levels compensate for polarizer rotation just about as fast as you can turn. So, it's a bit difficult to tell when you've reached maximum cut.

So what I've been doing is looking for a cloud or body of water or glass pane that has glare or haze, then looking to see what polarizer rotation gives it the most definition. This is working well.

The circular versus linear polarizing is a non-issue for the m43s because they are all mirror-less. Choose either, and note the linears are less expensive for comparable performance.

I enjoy polarizers very much, I use them more than the in-camera filters by far.

- Carl

This article is actually what prompted me thinking that I may have gotten a linear polarizer.

I would need to test this in the field then I guess. Thanks for sharing your experience with it.