I think "Natural" is the flattest profile. I also dial down the Contrast to -5, so I have more room in post. Saturation is set to 0 to get the most info out of color. Sharpness is set to 0 with my old fd lenses and -1 with the lumix lenses. I wouldn't set it to -5 as other suggest, because the video looks like it is out of focus and will require a lot of sharpening in post for sure. That means more post work and render time for me and I don't see any advantage at all. You may want to use this option in possible moire situations and try different sharpening values in post (I don't think moire is that common with Gh3). I leave NR set to 0, as I haven't had time to experiment with this setting. Enjoy your Gh3!