Most HDLR's have the mic on the body of the camera and most are monaural. One of the really cool things about the GH2 is the built-in stereo mic. I am really glad that Panasonic put the stereo microphone on the pop up flash of the GH2. It is wonderful to have cool ambient sound with my videos. I did the Irrigation Festival Parade with the built-in mic but no windscreen. I just set the camera up near the parade announcers. There was some wind noise and I started looking for a solution. I now have a windscreen on my onboard microphone.
I was looking for something to put on the mic with the flash not popped up. Just to cover the top of the camera. Somewhere I had read that some one had popped the flash up to put a windscreen on it. I put a foam windscreen from a small mic I had and it seemed to help but I wanted something better.
So now I was looking for the perfect windscreen. There where some foam screens for small mic's and recorders with mic's. I wanted something like a dead cat cover I had seen on shotgun mic's. Or as some call them, “fuzzy bunnies.” These screens have the best wind resistance.
In my search I found a company that sells all type of windscreens – Micover.com. Then, I had decide which one would work best with the GH2. I ordered a screen that is designed for the Panasonic HVX 200's on-board mic: Micover Slipover-Mini for Panasonic AG-HVX200A (On-Board) [MC-HVX-ONB] It cost about $20 and was sent out to me.
After some tests, I have to say the Micover HVX On-board Slipover Series works great. We had a fair amount of wind where I live so I could test it right away. I have done a demo video with and with out the windscreen.