Unfortunately, I had to put my GH2 away for a few weeks and totally lost some of my familiarity with it.
I'm spending time with my lost baby and finding out what I've forgotten.
Right now, what's confounding me is every time I hit Record, my pre-set ISO flips to "AUTO ISO" and trashes my shot.
SO glad I decided to play with it before taking a real shoot.
I've got the camera set to "M" and my ISO (currently) set to 640.
I've gone through my menus 4 (or 400?) times and can't find what I'm doing wrong.

ON a semi-related note: is there any "final answer" about which ISOs are best to use?
Last I heard, "they" said use multiples of 160. Or some said use 200, 400, 800, etc.
I haven't run any tests myself, so I thought I'd ask here.

Thanks for all advice, ideas and thoughts.

Yep... Like I said, "Newb."
Turns out I was on the photo "M," and failed to switch it to the video "M."
Need more camera-familiarity. That's why I'm playing with it.

Yes Matthew, the even settings generally are what people say are best. Someone posted a video with the various settings shown and the effects each had, and some were quite dramatic, but I can't tell you where it is.