BBC: 12 Stops Required for HDR Programs

From the BBC Academy Guide:

“The content needs to be captured in UHD. Specifically this means:

• using a camera and lens that can deliver a resolution of 3840 x 2160 pixels

• capturing at least 12 stops of dynamic range

If you’re making a live BBC programme you’ll need a camera that outputs hybrid log gamma. But Blue Planet II and Planet Earth II were shot in raw. Shooting in raw or log makes it possible for the wider colour gamut and higher dynamic range to be applied in post-production. For the HDR, you need to capture at least 12 stops of dynamic range.”

Definitions abound, but according to a study conducted in 2017, “Today’s television systems are known as Standard Dynamic Range (SDR) systems because supports [sic] a range of luminance of around 0.1 to 100 nits, about of three orders of magnitude or 10 f-stops. High Dynamic Range (HDR) is defined as any signal or device that has a dynamic range greater than SDR. An Enhanced Dynamic Range (EDR) system covers between 10 f-stops and 16 f-stops and a High Dynamic Range system supports a dynamic range of more than 16 f-stops or five orders of magnitude.” 

Those figures come from a 2015 MPEG document that greatly overestimates the range the human eye can perceive without adaptation.

Considering its importance to high dynamic range image capture, we find it interesting that dynamic range is not even mentioned in passing in Netflix’s minimum capture requirements, though practically all Netflix Originals as well as contestants in the world’s most prestigious film festivals are shot with cameras capable of encoding no fewer than 12 stops of dynamic range. Some entry-level priced cinema cameras, such as the Canon C70, are able to record RAW video with 12 stops of dynamic range, too. Most scholarly articles suggest something around 4 orders of magnitude as a minimum (with one paper citing greater than 3.3 as a more realistic figure).