Buying a new TV is a bloody nightmare at the best of times. You don’t ever want to buy one without seeing it first, but then when you go to the shop to have a bit of a snoop, they’re all in a special mode that makes all those colours way more saturated than is real, the brightness is all the way up, the contrast all out of whack. And now you have to try and figure out what on earth is going on with HDR as well?
With the PlayStation 4 Pro releasing later this week, HDR 4K TVs are quite likely clambering their way up on people’s wish lists. So here’s some of the things to take into account when buying an HDR TV.
Buzzwords and marketing terms
This is where the minefield begins. Every TV manufacturer seems to have come up with their own buzzwords to try and say the same thing. The main one to look out for is UHD Premium, the UHD Alliance determined term to show that a TV provides an excellent HDR experience. These TVs have 4K, can process 10-bit colour, have at least 90% DCI-P3 colour space and 1,000 nits (AKA cd/m2) peak brightness down to 0.05 nits for blacks (or 540 nits brightness and 0.0005 nits blacks for OLED TVs).
That’s the standard, but then LG has “HDR Super with Dolby Vision” – this is actually an excellent thing – Sony have “X-tended Dynamic Range”, Panasonic tout “4K HDR Pro”, and there’s “Crystal Colour” or “Quantum Dot” to worry about with Samsung, Hisense have “ULED” TVs that should not be confused with OLED. I’m picking and choosing here. They all mean something and nothing at the same time. A TV might not have UHD Premium on the box and still be an outstanding TV, but the UHD Premium mark is an industry defined standard and one of the easiest ways of cutting through the noise.
It’s a shame that not everyone uses it, then. Only Samsung and Panasonic have currently adopted it. So prepare to dive deep into the actual specs of a TV… You’ll have to forgive us, but it’s pretty jargon heavy from here on out.
Manufacturers aren’t likely to fess up to much, but the information is all out there. An excellent resource is displayspecifications.com, where you can simply type in the model number and get a wealth of system specs. Two other great websites are rtings.com (just beware of US model numbers) and HDTVtest.co.uk, though they have fewer TVs reviewed.
This is the screen itself, the bit with all the pixels on it that creates the various shades of colour, which are then lit by the backlight. For HDR, you ideally want a 10-bit panel, which means that each pixel’s red, green and blue sub pixels can produce 210 or 1024 different shades, which are then combined with the other subpixels to create a particular colour. 8-bit panels can only produce 16.8 million colours, but 10-bit panels have 1.07 billion colours to choose from.
Other terms for this are ‘Deep Colour’ (as opposed to an 8-bit’s ‘True Colour’), or 30-bit colour, referring to the combined number of bits of all three subpixels.
But beware, 10-bit colour can be faked on an 8-bit panel by using dithering, also known as Frame Rate Control or FRC. This uses slightly different shades of colour with successive frames to create the illusion of more colours. 8-bit+FRC TVs as still qualify as UHD Premium, as the TV is accepting a 10-bit signal, processing it and capable of displaying it accurately, but having a native 10-bit panel is naturally the preferred option. Some purely 8-bit TVs still tout HDR as a feature, at the lower end of the scale.
You might want to keep an eye on the colour gamut specs as well. To illustrate these, this spectrum represents all the colours that the human eye can see, while the marked triangles within show the colour spaces that refer to Rec. 709 (colours used in conventional TV, DVD and Blu-ray), DCI-P3 (a wider colour gamut that Apple has adopted) and Rec. 2020 (a recently defined range that has been adopted for the HDR10 specific). No TV is anywhere near close to full Rec. 2020 support, and even getting close to 100% of DCI-P3 is restricted to a select few.
Another panel characteristic to consider is the type. VA panels have better and deeper colours but tighter viewing angles, while IPS panels have wider viewing angles, but blacks suffer and often appear grey. OLED is the creme de la creme of display technology, widely seen in Android smartphones and now VR headsets. They’re hideously expensive, but since each pixel lights itself and can be turned completely off, they’re outstanding for HDR content.
OLED might not have to worry about backlighting, but LCD TVs most certainly do. There’s a few things to think about here, but the biggest factor by far is whether or not the TV’s backlight supports local dimming in any form. If it doesn’t, you won’t get the same kind of contrast in the same frame between light and dark. It’s a key part of the pitch for HDR TVs to have this feature.
However, not all HDR compatible TVs have this, and when they do, there are two types of backlight that affect how effective it is. Full-array backlights have hundreds of LEDs behind the panel, and local dimming allows for each of these to be adjusted individually. Edge-lit backlights have LEDs only around the edges of the TV, generally losing the precision needed to light only a small section of the screen without also blooming to the surrounding area. That said, it’s something that’s getting better and more precise over time.
The backlight naturally determines how bright the image is, and 1,000 nits peak brightness is the prerequisite for a UHD Premium stamp, though this doesn’t need to mean the entire screen is capable of outputting 1,000 nits all at once. 500 nits is still a very bright display, but again, having up to 1,000 nits allows for greater contrast between brightness and darkness within the same scene.
Companies very rarely talk about input lag, let alone put it in their spec sheets. The problem is that early HDR TVs, particularly those grandfathered into the HDR spec from 2015, often have high latency when dealing with HDR or 4K content. There’s usually a “Game Mode” on modern TVs to cut out unnecessary image processing, but then some older or lower end models don’t let you combine Game Mode with HDR.
Ideally, you want less than 33.3ms of input lag, which equates to a single frame in a 30FPS game. Samsung TVs have an excellent reputation for this.
While we don’t have any personal recommendations for TVs, there are a number of models that do stand out from the crowd.
Samsung’s KS7000 series is well regarded in some corners and come with a UHD Premium sticker and feature a very low input lag of 22ms, but they start at around £1000 for 49″. It should be noted that game mode with HDR was added via firmware to this series, but Samsung are continuing to tweak and improve this.
Eurogamer and Digital Foundry have adopted the Panasonic DX750 as their TV of choice. It’s cheaper – £849 for 50″ -, but for that step down you lose UHD Premium, as the peak brightness is only 500 nits, and local dimming is more basic. Input lag is slightly less than ideal, at 41ms according to DF.
However, these are just two possibilities from dozens, and each company has several tiers of TVs, ranging from around £500 up into the thousands, and many of them will be a marked improvement over a 1080p screen, both in terms of resolution and the range of colours displayed. However, there is a lot of variability, so make sure to look, then look a second, third and maybe even fourth before you leap.
My personal advice would be to wait until at least the middle of next year, at which point 2017’s range of TVs will be out and some of the more advanced features will be better within reach of the average customer. I still balk at the notion of spending £500 on a TV, let alone a thousand.