UPDATED:
I did some new accurate fine tweaking in the noise reduction presets and the new settings are saved for you to download and load it into your neatvideo. Also I saved all noise pattern profiles for all isos including etc mode, so you do not need to shoot the grayscale pattern anymore. The results are much improved. The link to download is in this site thread in post number 10:

personal-view.com/talks/discussion/1986/how-to-improve-low-light-image-quality-from-iso-12800-and-6400

Disable Adaptive Filtration can give better results if the noise is the same in all the video. Keep radius in 2 and threshold in 100.

The main slider control to tweak in Neatvideo is the Y slider. Use similar settings from the downloaded presets and increase or decrease the Y slider to get the look you want. Smaller values gives less plastic/digital look. In the presets I saved all the sliders were tested and saved in the best setting. for each iso.

Also It is very important to load the noise pattern profile at the same footage iso as showed. The noise pattern profiles are included in the download.

Get the noise reduction filter at neatvideo.com

I strongly recomend to use Cineform Neoscene to transcode the mts files to avi files before denoising. And, when denoising, always render the video as cineform avi as the intermediate codec. The denoised video image quality will be very better, a night and day difference.

Remember this: 1600 or 3200 iso is good enough for most low light situations if you have a fast lens. And 1600 / 3200 iso has a good quality in GH2. 12800 and 6400 iso is just for extreme low light situations.

In this video I did shoot some very dark situations, as you can see the luximeter shows 1 lux and also 0 lux (something between 0 and 1 lux). In these situations it was very dark and the camera see more than the human eye. The recorded image is lighter than it is. I used iso 12800 / 6400, shutter from 40 to 125 and the 55mm lens in f1.2 The camera can see more dark if you set the shutter to 25 and iso 12800 at f1.2.

In the other situations I needed to stop down the lenses and/or increase shutter speed to keep iso in 6400 and 12800. I could have used a lower iso. I just used 12800 and 6400 to show the noise reduction tutorial.

To see how good GH2 is at 1600 and 3200 iso without noise reduction see this video:
vimeo.com/26611738
If you want to denoise 1600 and 3200 iso watch the tutorial and use similar settings. You can download the neatvideo presets in the link above.

Hardware used in this tutorial:

GH2 Hack 40Mbps 1920 x 1080 24p
Cinema, Contrast 0, Sharpness -2, Saturation +2, Noise Reduction -2

Lenses:
Rainbow S48 4.8mm 1.8 (ETC mode) (rear focus barrel removed to fit c-mount/m43 adapter)
Sigma 20mm 1.8
Nikon 55mm 1.2
Lumix 14-42mm 3.5-5.6

Cheap crap tripod

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