I'm testing the GF2 in the evening with just the bedroom lights on, and I see a black line appearing on screen (along the height of the DISP. button). It is not straight, but is a little curved. When I darken the image by putting my hand in from of the lens, the line is very visible. The line is also visible when recording video in low light, but because the video is (still) heavily compressed, it is not pronounced. But when the patching begins it certainly will. I don't think it is visible in pictures. I shall take a picture of it with my GH2 later. Maybe I have a "dirty" sensor? Exchange it? Or is this a common problem?
No, it's not visible in stills I take in RAW or JPEG. Maybe also not in video. Too blurry to tell. It's just visible on the display. Pretty visible horizontal dark line. Maybe some interference? Strange. Have not seen this before in any of my MFT cameras, except for the more faint banding on the GH2.
Don't see a problem in the RAW pictures. Pretty clean sensor. Only visible on the GF2 screen in Live View when composing, when bottom half of frame is underexposed compared to top. Especially visible when I press the autofocus! The image turns a little darker during autofocus and the line becomes pronounced. Have to test more in video, but I really don't know what ISO is used, so it's somewhat useless.