@stonebat

"Saturation 0 or -1 might have reduced some color noise."

Perhaps, but my personal aesthetic is for rich, detailed colors.

132 definitely has finer noise reproduction. No question about that. Some people will find it useful. But shorter recording time and possible in-camera playback issue. I'm sure some people wouldn't mind that.

We are learning more pros and cons. I like the details. Hopefully the same testing can be done when we get new PTool as VK and Chris are working on improving the codec.

@Ralph_B

I like rich color, too. But sometimes lighting condition makes some color to clip. The streetlight might have clipped green color on the trees.

No this is not a complaint. I appreciate your testing.

"Also, be aware if you can see more finer noise, this means you are able to see more fine detail which results in a better detailed image."

+1

And let's not forget, the GH2's ability to resolve fine detail is one of the things that sets it apart from every other DSLR on the market. This is it's strength. So it makes sense to maximize it. cosimo_bullo is using it in conjunction with Red 4K. That speaks volumes.

@stonebat, I think so, yes. Finer, more detailed grain has a more filmic feel - and if you want to clean it up, you're starting with a much more accurate source than if NR has already been applied or compression has smoothed it over.

This might not be directly related with what we are discussing here, but quite interesting article about computer generated noise. http://www.scratchapixel.com/lessons/3d-advanced-lessons/noise-part-1/introduction/

Noise is band limited. Remember that noise is mainly a function, which you can see as a signal (if you plot the function you get a curve which is your signal). In signal processing it's possible to take a signal and convert it from spatial domain to frequency domain. This operation gives a result from which it is possible to see the different frequencies that a signal is made of. Don't worry too much if you don't understand yet what it means to go from spatial to frequency space (it is off topic here but you can check the lesson on Fourrier Transform). All you need to remember is that the noise function is potentially made of multiple frequencies (low frequencies account for large scale changes, high frequencies account for small changes). But one of these frequencies dominates all the others. And this one frequency defines both the visual and frequency (if you look at your signal in frequency space) appearance/characteristic of your noise function. Why should we care about the frequency of a noise function? When the noise is small in frame (imaging an object textured with noise far away from the camera) it becomes white noise again which is a cause of what we call in our jargon, aliasing. This is illustrated in the following figure (xx).



If it is possible to completely disable the noise reduction, we might see more finer noise which might become white noise or aliasing. It will look better only if it goes through post-processing to remove the noise. Of course the consumer camera manufacturers wouldn't want that as most consumers would prefer seeing more coarse grained noise. I meant for video. The white noise aliasing would freak out most people who are not into videography.

Question: What GOP is recommended for 720p?

Thx!

Thanks for the quick reply. And thanks for all the great testing and info.

Chris,

there's other interesting info at
http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Panasonic/Lumix-DMC-GH2
under 'measurements'

Color sensitivity, tonal range, everything drops significantely with rising ISO

@stip

Nice chart - thanks. It sure looks like ISO 800-1600 is the breaking point - as the SNR there is pretty close to 0.4% (accounting for 250 steps, or so).

@cbrandin - These are interesting points, but they're very theoretical, and, thanks to Ralph, we no longer need to operate in a theoretical mode. Everything should be tested, even if it seems the numbers don't add up.

"It looks like after ISO 1600 the codec will outperform the sensor. Actually, considering Nyquist limit, etc... it may outperform the sensor at 800."

The codec - other than the one night time 132M test - is clearly not outperforming the sensor in any mode. There's a lot of valuable info/noise that is being dumped, info/noise many want to keep if at all possible. Remember, this is art as much as science.

And, to be clear, I SO value what you are doing, Chris, just want to be clear that Ralph's tests have changed my thinking dramatically as to what's possible.

@Ralph - a small request (one in a series...!). While you're doing your HDMI testing, can you also include a 1080 jpeg photo taken with the same settings. I'd like to see how different the jpeg looks from the HDMI signal and see if that could be used as a low-tech baseline for future tests for those without HDMI capture.

Good, thanks for clarifying Chris, and for your enthusiasm for this whole thing; great fun for me to be a small part of it.