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Vitaliy Kiselev revealed his latest version 3.63 GH2 hack yesterday. In it is a innocuous patch that removes the ISO limit (3200) in video mode allowing us to go all the way to ISO 12,800. Now at first I didn’t think much to this, since the image would be unusable at ISO 12,800 right?
Well it turns out I was wrong.
“Seeing in the dark is an understatement, it is like having Infra Red!” was overheard on Vitaliy’s forum so I went out in a hurry to test it and recorded the footage above at ISO 12,800. What I found amazed me. The amount of detail still present in the image is just astounding. No noise reduction is applied to the footage, and it is turned off in-camera. Not only that but noise has a very fine film-like grain because of the accompanying high bitrate hack. The look of the noise is similar to the Nikon D3S’s video mode at high ISOs but with far more resolution. It doesn’t look like digital noise, it is more like 8mm film at ISO 800.
Hacked or not – to cope at ISO 12,800 and produce a usable image let alone one so attractive I thought was impossible. But if you think about it there are several reasons why it works. Bitrate, film mode, the GH2’s advanced scaling / pixel binning.
1. The high bitrate hack, be it 44Mbit AVCHD or 176Mbit AVCHD All I-frame allows the fine grain of the noise to be maintained and not smudged, furthermore it allows an incredible amount of resolution and detail in the image to be maintained.
2. Switching the camera to Dynamic B/W film mode reduces low contrast areas of the shot and electronically boosted shadows where noise tends to be most intrusive. The results are stunning, it is like having night vision or Infra Red. Blacks are a little crushed but at this level of exposure it doesn’t really matter – just over expose slightly.
3. Lastly the sensor scaling has a lot to do with it. At 1:1 the image would be hideously noisy but since a full 16MP sensor is being scaled to 1080p grains of noise are absolutely tiny making noise look more organic and film like. Also due to the nature of the CMOS sensor, brighter areas of the image are virtually noise-free if you use a fast aperture.
I love the fine 8mm-alike grain, along with black and white. The camera was so sensitive at ISO 12,800 that I had trouble finding areas of Shanghai that were pitch black enough.
The video above was shot entirely at ISO 12,800 with noise reduction turned OFF in-camera. That way so much detail survives that it allows you to carry out very effective professional noise reduction in post using plugins like Neat Video. This makes more sense than in-camera N/R because your editing workstation has far more horse power to throw at the job than the camera does, and it can take its time rather than having to do it slap-dash in realtime.
But here’s the kicker – I liked the look of the noise much I didn’t do any noise reduction in post and the video above is straight out of the camera un-graded!
You can get almost clean ISO 12,800 out of the camera with Neat Video whilst preserving most of the details stored at the hacked 44Mbit bitrate.
All in all this really turns things upside down, instead of seeking out enough light I was seeking out enough darkness. I was using the Voigtlander Nokton 25mm F0.95 and wide open at ISO 12,800 as you can imagine is just mind-blowing-freaking-crazy. In a dark ally I could wave my hand in front of my face and not see it, yet it would be a mid-tone on the camera.
I also used a SLR Magic 12mm F1.6 for the wide angle shots and found myself stopping it down to F4 for many of the shots in the dead of night just to avoid over exposing. The streets were not brightly lit, it wasn’t the centre of town. It is amazing how many subtle flickers of light bouncing off buildings the sensor picks up which your eyes miss or barely register. One street was lit by a single bulb and it felt like day time in-camera. I suppose it was inevitable that human vision would eventually be usurped by digital but I didn’t think we’d see it first on a sub $1000 Micro Four Thirds camera.
Technique wise at ISO 12,800 it is best to overexpose a little and darken in post if necessary because noise is lower over brighter areas of the frame and higher when underexposed due to the nature of the CMOS sensor. By overexposing you are increasing the signal-to-noise ratio. I also find it helps to turn the brightness down on your playback monitor or laptop screen otherwise it emphasises the grain and not the tones and details present in the image – of which there are abundant amounts. The tonality of the image is really excellent in Black & White film mode because the camera doesn’t have to worry about colour, so an 8bit codec isn’t as much of a handicap. It pumps all of those 8bits into black & white and is far happier as a result.
I heavily recommend this film mode if you are using ISO 12,800 since it reduces luma noise and colour doesn’t exactly look great in the middle of the night because objects aren’t getting enough illumination to really give out any hue.
Overall I am shocked astounded and amazed about what Vitaliy has been able to do here. Compared to the low light performance of the EPIC or Scarlet the GH2 absolutely floors them.
