I'm a newbie (those dreaded words!)

I've recently got a GH2 and mainly use it for filming. I'm now looking to get some filters for it (polarising and variable ND) purely for video.

Initially I thought I'd just buy screw in filters, namely the digital ones from Hoya but it quickly dawned on me that that would be an expensive option as it would mean individual filters for each lens due to the different thread sizes on each of them, also I have one which doesn't take filters ( the Panasonic 7-14mm wide zoom).

I then thought that a good option would be slot in filters such as the Cookin variety, as a cheaper option to the screw in type. Also with the slot in filters I would be able to filter the Panasonic 7-14mm? However these filters I understand are made of resin (plastic) so would I be right in thinking that they would not be ideal for filming, not as good as glass screw in filters?

I'm confused to say the least!

I'm contemplating just buying uv filters for all lenses (for protection) and getting a polariser and variable nd one screw in just for my main lens ( the panasonic 14-140mm).

I'm just imagining myself on a sunny day and wanting to reach for 7-14mm panasonic but then thinking "Gee wizz Batman, I can't polarise or use an nd on this" colours could turn out washed out due to reflections, I guess the nd issue could be resolved by stopping down the aperture as I wouldn't get a shallow depth of field on this lens anyhow :-P

I understand a lens as wide as this just isnt possible to have a thread (vignetting issues, protruding lens,) so do I guess the best thing i can do is just stop down on sunny days but no solution for the polarisation?

Thanks

Rafael