Saturday, October 10, 2015

Actual visible benefits of hacking the GH2 and how to access them

Ok, I'm in deep research mode and the blog is once again my notebook. 4th info-heavy post today:

This is from a thread about the actual visible differences between the hacked and unhacked GH2. I need to understand it and learn how to take advantage of the benefits:

"The hack version brings some subtle for some but big improvement to someone like me. There are three aspect where I find big big improvement, I put them in how the hack unfolded.

The first thing was the codec in motion (not shown at all in the above test). The hack does improve the image quality when in motion, you will see it much better in high detail scene. No more image breaking up when panning etc. Some have developed low gop settings that they claim result is much more filmic (with the latest ptool there is a bug which is causing some inconsistencies, while it brought 1 gop... avcintra territory).

The second thing is in the shadow details ala dynamic range. Where the base codec was smoothing any underexposed area, the hack just preserve the detail below (it even preserve the noise!!!). Just boost your gamma in post a little and see how those macro-block just pop up. Now you can meter to a certain level for the highlight and recover by boosting the shadows in post, effectively the hack has increase the dynamic range of the gh2. By 1,2, ... stops!!! until further test I don't know, but it is quite substantial and something huge for me. I would like to know (test) what happens to the highlight also, if the same principal applies because the codec is geared towards what I would call normal viewing. That is it cuts details where normally mister consumer won't see, more so in motion, to achieve higher efficiencies.

The quantization/gradient/banding setting from the latest ptool. This is another huge improvement from the hack. In the previous iteration of the hack it was seen that even if you could achieve some high bitrate on detailed scene, on lower detail scene the birate would decrease a lot and could be the cause of the gradient/banding on large surface of flat colours . The prime example being blue sky where the gh2 exhibited a lot of banding, even a bit more compared to other 8bit camera. Again I think it is the consumerist nature of the avchd base codec, tuned primarily toward efficiency before quality. With the work of Chris and Vitaliy they have enhanced/change the base setting resulting in high and more constant bitrate across the board, and the gradient/ banding is greatly reduced.

When you take all of the above for me the GH23.VK is a much much better camera than the base gh2 (which was already good) and as someone at personalview who has a red says "I'm a RED owner and am truly amazed at what I'm seeing" . Now, if you are going to shoot some family or tourist shot the hack is surely unwarranted. But if as me you intent to do quite some image manipulation, heavy grading etc, the GH23.VK makes a huge difference. The base image breaks down much much faster than the hacked one."

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