HDR – What’s it all about? (The non-technical version)
By Andrew Devis (doddleNEWS)
It seems that we’re confronted with the next ‘must have’ technological revolution in TV every couple of years, but as you probably know, many of these ‘wonders’ have ended up as being little more than curios with limited long-term widespread appeal. For example, stereo 3D has a limited place in film and some like it for sports, but no one’s really talking about it now.
Virtual Reality is a reasonably new thing for mainstream video, but hasn’t really found a champion ‘killer app’ to take it out of the gaming world and into mainstream TV production, and in the writer’s opinion, it simply won’t because narrative storytelling needs to direct and drive a narrative, while VR allows the viewer to be looking anywhere except where the action is happening at the crucial moment (end of rant). HFR (High Frame Rate) is another thing that people have got excited about but which we hear less and less of except in ‘experimental’ movies and the like, and somehow hasn’t lived up to the hype.
Even 4K UHD (Ultra High Definition) TV has failed to be a really big influence in the uptake of new TV sales – not least because it seems that you need at least a 50-inch screen to actually see the difference UHD makes over a good HDTV! So, can HDR (High Dynamic Range) TV hit where all these others have missed?
In short – yes it can!
And here’s why: The human eye can process a tonal range (that’s levels of brightness) of about 20 stops (1 stop would be either a doubling or a halving of the light level) and present high-end cameras can capture about 14 stops or more. Our current TV systems are all based on the standards that were set when everyone had tube TVs (you remember those huge, heavy lumps we tried to squeeze into the corner of our rooms a few years back). In fact, our present TV systems aren’t based on the tubes we grew up with – they’re based on the original tubes from yesteryear (1940s/50s) and haven’t changed much since!
And that’s the problem, because even though technology has raced ahead in recent years, because of backwards compatibility with older TVs, the broadcast systems themselves restrict the tonal range (bright and dark) and the color range (color gamut) to work with those old old old TVs. That means we see 20 stops, good video cameras can capture up to 14 stops but our TV can show only 6 stops – it’s the same with the range of colors – present systems can show around 33% of the color ranges our eyes can actually see!
Luminance Dynamic Range
But HDR TV, which includes not only a much wider tonal range (bright to dark), but also a much wider color range known as WCG (Wide Color Gamut) is changing that significantly, offering up to 10 stops and up to 57% of the colors our eyes can process. You may not think that sounds very impressive, but believe me, when you actually see its you realize that this is a VERY BIG DEAL, and things are still evolving, fast!
This image shows the colour range (gamut) of our present TV systems (rec. 709) and the new HDR systems (rec. 2020)
So, while UHD TVs offer more pixels at higher resolution, HDR makes those pixels work to produce incredible life-like images with details in the darks and brights that simply weren’t there with the old broadcast systems, which in turn plays on our brains, producing physiological and psychological responses! Yes! It can actually have a much greater impact on the way you feel than anything standard TV can do – the difference is visceral – and once you’ve gone there, there’s no going back…
Standard Dynamic Range vs. High Dynamic Range video
Note: While I can show pictures in this blog trying to represent HDR, please bear in mind that to view true High Dynamic Range, you really need an HDR-enabled monitor – so images are for reference only. One good HDR reference is the Sony BVM-X300, now up to Ver. 2, though it’s not available to buy. Price could be over $20,000, and some HDR pro UHD monitors can cost up to $50,000!
Another option is the excellent LG OLED series, including the 65-inch E6P-Series 65, which retails for $4500 at B&H as of this writing. It’s being used as a more affordable reference monitor. There’s also a 55-inch version for $3000 at B&H as of this writing. [Note: Affiliate links.]
In part 2, I will discuss Nits and more (click here).