Most important: Proper exposure! Often banding is a sign of too low exposure that you try to boost up in post. (This is due to the fact that the cam uses less bits for the darker areas than the lighter ones.) Don´t be too afraid of noise, you can fix (alot) in post. I go up to ISO 3200 with GH2. (This only works with top quality Intra settings from Driftwood in my experience.)

Next step is (after you are done cutting your clip and copypasted timeline over to After Effects) to trow some denoiser onto your footage. I prefer Neat Video but Magic Bullets Denoiser isn´t that bad as well. Turn on Interframe Processing, (3 Frames for Neat Video), so the plugin can look into future and past a bit. This will already fix alot of the banding (make sure your After Effects Project is at least switched to 16 bit, so the oversampling can take place.)

If your clip still suffers from banding you can try to duplicate the layer and apply noise reduction with much stronger values (I found that MB Denoiser is better in creating smooth gradients in high settings than Neat Video). Then do some kind of chroma key (or whatever keying type suits your needs) onto the surface that suffers from banding. This way the parts of the picture that contain details will not suffer from plastic look, while the parts with gradients will be much smoother. (Don´t forget to renoise these parts a bit, so they will not stick out.)

I usually add some very subtile film grain on top of everything (Transfer mode: Screen or multiply, Opacity 10-25 %). This will dither a bit and - while the clip stays well compressable - add a bit analog feeling.

Hope that helped.

@matt_gh2

Expose for the areas which are at risk (of banding) such as monochromes.. If possible. When it comes to skies, they are generally in the top 20% and are hard to get below that without crushing everything else. Noise (dithering) helps to make banding or stepping less obvious. So this goes both for capture and for delivery. Grade/Color in 32bits = will help to not worsen any potential problems.

Why it is always necessary to make new topics?

http://www.personal-view.com/talks/discussion/202/gh2-banding/p1

It's pretty hard to avoid but I often find myself desaturating areas and recoloring in DaVinci to mask the 8 bit look.

Attached are examples, the raw, the gamma curve applied, and the final. You can see in the Gamma Curve image, near her neck, ear, and jaw line, the image starts to fall apart color wise. This required quite a bit of massaging in post.

+1 itimjim - a bit of noise captured in the image, and then NR in editing, will dither the 8-bit posterisation and then removing the noise gives you a nice clean image. Noise reduction is so amazing nowadays.

Where you're really pushing an extremely low-light image you also get that fixed pattern noise (sort of reddish colour) that's just horrible. But then again, you probably wouldn't be getting into a situation where you'd have to do that sort of major rescuing on an important shoot.

@artiswar Have you ever used Davinci's noise reduction?

@retrospective - I'm using the lite version so it lacks the NR. I've got Neat Video which was applied to the above clip post-grade. Regrained with an overlay I made in AE using the grain plugin and a grey solid.