Does the Canon 5D2 handles banding better than the GH2? I've sold my 5D some time ago and I can't remember whether there were much banding.
My GH2 banding (posterisation) is especially pronounced when watch on a 50 inch Panasonic VT25 plasma panel. On a 24" Apple Cinema Display, the banding was less of a problem because I reckoned it was heavily dithered.
//Moved from original location// Exposing to the right saves the trouble of using LCD for anything but framing (EVF is better for focusing). the point of exposing to the right using the histogram is precisely that ( I would also turn on the highlights blinking) you will get a good exposure without picture confirmation. Good exposure in that sense that you record maximum tonal information, the image might look washed out unless you grade it in post. Low contrast Nostalgic or Cinema are always good. Though honestly I rarely see gradient problem with what I get out of GH2. For me the real reason to expect the hack is so that codec would give more attention to the areas that are below the mid-tones so when I try to grade them up if needed there would be actual detail and not just areas of flat fill with squared edges. There is no fix for sky banding short of 8bit>16bit>color key for the sky color>blur keyed region>apply noise to the keyed region only and it must match unaffected areas or will look fake. And it is very tedious and slow, and painstaking. So no - there is no fix. To answer for Vitaly no probably there is no easy way that 10bit color can be enabled (as he only tweaks existing firmware and does not write new one, it also may be hardwired so no firmware may change it)
I think its like dkitsov explained it. Dark saturated gradients like a blue sky at dusk will alway have banding issues on a GH2/AVCHD/h264. There are h264 profiles that support 4:2:2 chroma and more than 8bit. I don't think that they are implemented into the AVCHD encoder inside the GH2. A higher bit rate could help to avoid compression artifacts for high detail fast motion shots but it wont be that helpful for color banding issues.
Color is a real issue on the GH2. To me, this greenish tint and the banding are a way more often experienced problem then rolling shutter and aliasing on the Canons I use. And its very hard to fix the green GH2 look in post. You have to plan your GH2 shoot even more carefully than you have to with the Canons.
I've seen this gradation step issue, although normally it's almost unnoticeable. In one case though the steps were actually moving across the picture (in one direction, diagonally) where there was a flat area of white wall in the image. This was with a manual lens and fixed exposure, so the exposure wasn't changing. Therefore I'm not sure what was happening there and why the steps were constantly moving across the image. That's the only time I've really noticed it, and it was in a shot with a single bright area (a window) elsewhere in the frame, so maybe that was affecting the exposure enough to make the gradation steps visible. Still don't know about the movement, though.
Dkitsov's idea about changing exposure is an interesting one - not one I've tried. But then, I've not seen the gradations on the LCD, only afterwards, probably because the LCD seems to go to a slightly lower quality during recording, so I wouldn't have been aware of it at the time I shot the footage. But something now to watch out for in particular scenes.
@dkitsov, you mention that this is essentially a LF effect - which I suppose it is - so I wonder if there's any post-treatment (chroma blur?) which can improve it?
Also, do you think that by changing the in-camera contrast settings, it could help to use more of the values available where it matters?
Finally, Vitaliy, any chance of the hack making it possible to record 10 bits per channel? One can always hope!!!
Edit: have looked again at the shot with the moving banding. I was very slightly changing exposure during it (just playing around with a new lens). But in a more conventional shooting situation, I could see how you might get that effect of changing exposure with lighting / shadows that vary during a shot.
rozor is right, however higher bit-rate will help somewhat by allowing codec of the camera not only to concentrate on the areas of high frequency detail in Lightness and color channels (more attention is usually paid to lightness information channel) but also on the areas of low frequency like the sky. Sky is the area of the continuous tone but its appearance does not only comes from lightness info: Blue/Yellow channel is also very important. You won't necessarily get film like appearance of smooth tonality change with a higher bit rate but you should certainly get gradation steps that are more smooth themselves and look more like a film to digital transfer, rather than digital acquisition to begin with due to the reduction of the macroblock patterns. That being said if sky gradation is really important to you try so called expose to the right (using a histogram) method and then color grade to bring down you mid-tones and shadows if they appear to be too bright. By exposing to the right you will be able to squeeze more of those 256 values per channel available where it is important to you. Exposing to the right is a good practice for any kind of subject matter anyway, but you will have to color grade in post.
With proper exposure, and watching your highlights you can get great results. "BUT" I still get contour banding on out of focus areas, sky, and graduations in light falloff. As far as i can tell, only a higher bitrate will allow the codec to not through out all that graduation. So if it is 150 mbs I take it, to get smooth images. We will see if 100mbs+ will even be possible on a GH-2?