GH5S Hits Broadcast Quality Benchmark in EBU Tests
The Panasonic Lumix GH5S has been tested by Colour Science Expert Alan Roberts according the European Broadcasting Union R.118 guidelines and, as a result, it is effectively approved for Broadcast use in HD and for second camera use in UHD productions. For acceptance in the EBU Tiering system, the camera should be used with the optional DMW-XLR1 sound module to allow for XLR audio connections.
These camera tests produced a great result for the Lumix low-light champion, and also revealed some unexpected findings. The full report can be read on the European Broadcast Union’s website, and will also be hosted by the Guild of Camera Professionals.
Although the EBU testing cannot be considered an endorsement, getting through the tests is a big feather in the cap for the Lumix engineers at this price point. Many productions are already using the GH5S and this result will give producers even more confidence in their new choice of small camera.
The report states “Resolution at HD is very good, with very little spatial aliasing. ~ This confirms that there is a good optical low-pass filter in the camera, and that the down-scaling to 1920x1080 HD is done with a good algorithm.”
Decent optical low pass filters are notoriously difficult to create at lower costs, and are key to a camera producing clean pictures, which even at the end of a complex production and encoding chain, will remain pristine.
Another section states “Colour performance is good and there was no evidence of any Infra-Red response.” This is important, because not all lower cost cameras include a decent IR filter. As an aside, it's worth noting that IR response testing is easier than you might think, just by looking at the camera’s screen and pointing an IR TV Remote control at the Lens. If you see the LED your camera can see IR and your colours will be polluted.
Home, Home on the Dynamic Range
“The dynamic range is about 14.6 stops in HLG, a creditable performance. CineLike-D is about 13.9 stops and Like709 about 10.3 stops with the Knee switched off. However, all of this is using the 4:2:2 10-bit recording modes.”
Of course the Lumix GH5 and GH5S are unique in their internal 10-bit SD card recording for their cost and form factor. It’s simply impossible to record high dynamic range without 10bit recording.
Not making a big noise
“The EBU R.118 noise-level target at mid-grey for HD Tier 2 is -44dB, which the camera meets comfortably in all modes. The target for Tier 1 HD is -48dB which is also met using all modes. Best performance appears to be at ISO 2,500, with noise deteriorating at both higher and lower speeds. For UHD, the noise target of -50dB can be met at some ISO settings.” Low noise is a key to more dynamic range, because detail can be pushed out of shadows in the grade.
“Somewhat surprisingly, far from reducing the effective resolution, noise reduction appears to improve it. So there appears to be little reason to avoid it, and the higher settings may well be acceptable. If so, then a further 2dB improvement in noise (but only when the noise levels are already high) might be achieved. This is encouraging, if rather surprising.”
This unexpected result means even in low light situations the cameras on board noise reduction can be trusted to get decent results without a big resolution trade-off.