Update: Can't find anything to watch in Ultra-HD? Check out our guide to 4K TV show and movies!
4K: Everyone wants it and no one knows why. It's the hottest techy buzzword of 2015, and it's a technology that's rewriting the rulebook when it comes to image quality.
It affects not just the world of 4K TV and cinema, but also cameras and image capture, smartphones and tablets, computer monitors and PC games - practically anything that displays images or records video.
4K TV sets are now available from most of the major TV manufacturers - i.e. Sony's impossibly slim Android TV or Samsung's SUHD series of TVs - but they're merely the tip of a very cool technology iceberg.
But before we get ahead of ourselves, let's make sure we all understand the basics. What the heck is 4K and why should you care?
What do I need to know about 4K?
In a minute we're going to explain precisely how 4K is defined, how it works and why you should care, but to tell you the truth, you only need to know one thing about it: 4K means more pixels.
How many more pixels are we talking about?
About 8 million. Which is around four times what your current 1080p set can display. Think of your TV like a grid, with rows and columns. A full HD 1080p image is 1080 rows high and 1920 columns wide. A 4K image approximately doubles both those numbers, yielding approximately 4 times as many pixels total. To put it another way, you could fit every pixel from your 1080p set onto one quarter of a 4K screen.
Why is it called 4K?
Because the images are around 4,000 pixels wide. And before you ask, yes, the industry named 1080 resolution after image height, but named 4K after image width. For extra added fun, you also might hear this resolution referred to as 2160p. Welcome to the future. It's confusing here.
Do all those extra pixels matter?
They matter very much. More pixels means more information. More information means sharper pictures. Sharper pictures are more engaging. More engaging content is more fun. And fun... well fun is the thing, isn't it?
So I'll see a huge difference?
That's where it gets sticky. We're talking about a similar jump in resolution as the one from SD (480 lines high) to HD (1080 lines high). And 4K screens are noticeably sharper than 1080p screens. But there are a few reasons you might not feel the same thrill you did when you upgraded your old CRT to a flatscreen.
When most people went from a 480 to a 1080p set, there was a good chance they were making a big jump in TV size as well. In terms of wow factor, display size is more powerful than any resolution jump could ever hope to be. Last time around most people got big jumps to both screen size and resolution. But this time screen sizes are staying about the same, with the most popular models falling in the 40 inch to 70 inch range.
Most importantly, though, you'll only be able to see the resolution difference on a 4K set if you're 1) watching 4K content through it and 2) you're sitting close enough.
Sitting close enough?
Yup. Remember when Apple made a big fuss about "retina" displays a few iPhones back? "Retina" refers to screens that have sufficient resolution that at a normal viewing distance your eye can't make out individual pixels. Get far enough away from a 1080p set and, hey presto, It's a retina display! More importantly, at that same distance, your eyeballs won't be able to squeeze any more detail out of a 4K image than a 1080 one. If you're at "retina distance" from your 1080p set now and don't plan on moving your couch closer, upgrading to 4K may not make a big difference to your experience. This chart shows how close you need to sit at any given screen size to see the difference.
So I should sit closer?
Oh my yes. The ability to get up close to the screen without the image breaking down is one of the most intoxicating things about 4K. Sitting closer allows the same sized screen to fill more of your visual field, which yields greater immersion. The up-close factor is one of the reasons 4K computer monitors have become one of the technology's fastest growing sectors. 4K monitors remain pin-sharp even when you're just a foot or two from the screen, as you are when you're sitting at your desk.
Difference between Ultra HD and 4K
Technically, "Ultra High Definition" is actually a derivation of the 4K digital cinema standard. However while your local multiplex shows images in native 4096 x 2160 4K resolution, the new Ultra HD consumer format has a slightly lower resolution of 3840 X 2160.
This is one reason why some brands prefer not to use the 4K label at all, sticking with Ultra HD or UHD instead. However, the numerical shorthand looks likely to stick. As a broad brush label it's so much snappier!
Why should I care about 4K Ultra HD?
There are many reasons why 4K should make you rethink your next TV purchase (actually, there are eleven and you can read about them here), not all of them immediately obvious.
Photographers who routinely view their work on an HD TV are seeing but a fraction of the detail inherent in their pictures when they view them at 2160p.
A 4K display reveals so much more nuance and detail – the difference can be astonishing. While 3D has proved to be a faddish diversion, 4K comes without caveats. Its higher resolution images are simply better.
The higher pixel density of a 4K panel also enable you get much closer without the grid-like structure of the image itself becoming visible –this means you can comfortably watch a much larger screen from the same seating position as your current Full HD panel. Currently all available 4K Ultra HD TVs are in excess of 50-inches.
You also said "and up." Can UHD also designate higher resolutions than 4K?
Yes. This is the slightly confusing part. An 8K display would also be UHD.
What is this 8K you speak of?
It's the next resolution standard up from 4K. Basically it doubles the pixel height and width again to yield approximately 32 million pixels. It's a regular pixel party.
That sounds awesome. Should I just get one of those?
Absolutely not. The 8K standard is primarily for the exhibition market (aka movie theaters). To make that many pixels matter, you need to be feeding a truly gigantic screen and sitting right in front of it. Besides, you can't buy an 8K screen today without having it custom built, which would cost approximately seven hojillion dollars. And there's no commercially available 8K content. You'd need to get movies directly from distributors the same way theaters do. You do not need this unless you are Jerry Bruckheimer. (If you are Jerry Bruckheimer, though, give me a call. I know a guy.)
My friend told me about 4K OLED. What's that?
More acronyms! Isn't this fun? OLED - organic light emitting diodes - have been around for some time, but producing big screens using this technology has proven to be prohibitively expensive, something which has so far prevented OLED television from being a mainstream proposition.
It's a real shame because OLED technology can be stunning, offering vibrant colors, deep blacks and bright whites. But don't give up hope just yet. Several companies (most prominently LG) are laboring away to bring OLED to 4K televisions. We recently took a look at LG's new 4K OLED sets, but while they're gorgeous, pricing remains sky high. Hopefully that will change soon, though. "I believe the price and yield rate will be higher immediately and the price will be down," Mr K I Kwon, president of LG Electronics UK, told TechRadar recently. We hope his predictions hold and we aren't ruling out OLED as a big player in the next generation of televisions.
I've heard Netflix is going to start streaming in something called HDR. What is that?
HDR, UHD, OLED ... there's no shortage of acronyms in home entertainment.
HDR, or high dynamic range, is a concept borrowed from digital imaging which combines three images - one with normal lighting, one with underexposure and one with overexposure - to give more contrast to an image or video. Netflix will be the first content provider to release HDR video in 2015.
You won't necessarily need a UHD screen to get it, but to really see a difference in picture quality you'll want to step up to the higher resolution.
Quantum Dot sounds like theoretical physics
It does indeed. But unlike some problems in theoretical physics, the solution is already here. Quantum Dot displays (QD for short) are simply LED panels with a thin film of nano-crystals in between the backlight and the display. Manufacturers like LG and Sony claim that this increases color depth by around 30% without adding extra pixels or implementing a wacky algorithm to digitally manipulate the display.
We went hands on with a few QD panels at CES 2015, including the LG UF9400 Quantum Dot 4K UHD TV and Samsung SUHD Curved TV, which uses a variation of Quantum Dot. We liked what we saw, mostly, and especially on the Samsung SUHD. The LG had some issues with oversaturation ... but that may be fixed by the time the TV comes to market in Q2 2015.
What about 4K content? Can I get that?
Yeah, about that... There's actually not much 4K content to be had right now.
Because every 4K frame contains four times the information of HD, 4K content is four times more bulky than regular HD content in terms of its raw file size. That makes it a challenge to get it to you. Broadcast TV hasn't made the 4K switch yet (indeed, it's only recently that hard drive sizes have gotten big enough to manage DVRing HD programs comfortably). There is a 4K Blu-ray standard coming, but the Blu-ray disc association is only just finishing it and won't start licensing it to manufacturers until early 2015. Victor Matsuda, chairman of the Blu-ray Disc Association Global Promotions Committee told us we should see 4K players and discs in time for the 2015 holidays.
On the streaming side, bandwidth is a definite issue. The internet's bandwidth is already dominated by Netflix's traffic, prompting ISPs to go after them for extra cash, and that's with most of its streams at SD and HD levels. Upping everything to 4K doesn't sound like a reasonable option just yet. And even if it were possible to stream 4K content to everyone without breaking the internet, streaming 4K content requires a 25Mbps or faster downstream internet connection, which is faster than most people have at the moment.
So what can I watch?
The good news is many new films and some TV shows are now filming in 4K as a future-proofing measure. The bad news is all that content will have to wait until we have established avenues for getting it to people. Your best UHD options right now come from Sony and Netflix, with Amazon to follow suit this fall.
Sony launched its Video Unlimited 4K service in 2013, which offers more than 70 films and TV shows for rental or purchase. It requires Sony's 4K Ultra HD Media Player, the FMP-X1 ($350), which comes with a 2TB hard drive and is only compatible with Sony 4K TVs. 24-hour TV show rentals are $4 and 24-hour film rentals cost $8. Film purchases are $30. It's not exactly instant gratification, though. Once you rent or buy something, it needs to download to your player, which Sony estimates can take 8 to 15 hours, depending on your Internet connection, so you'd better think ahead if you're planning a 4K movie night.
If you want to watch right away, Netflix is testing the 4K streaming waters with select shows (House of Cards, Breaking Bad, The Blacklist) and films (Ghostbusters, The Smurfs 2) if you own a Samsung, Sony or LG 4K TV and have a 25Mbps internet connection. Currently, however, the content selection is limited at best. And contains The Smurfs 2. Netflix has announced that it will require new subscribers to be on the highest tier four-stream Family Plan in order to access 4K content. Existing subscribers will be grandfathered into 4K for two years on their existing lower-tier plans.
In addition, Amazon recently announced that it would begin streaming 4K content to TVs by select manufacturers in October. By the time the holidays roll around, it looks like 4K pioneers will have at least a few options to choose from.
Is it me or are those options are almost comically limited?
It's not you.
Why are we even talking about 4K then?
Because it's awesome. Seriously, the pictures look amazing. You're going to love it.
How does that help if there's nothing to watch?
It's a fair point. There is definitely a chicken and egg problem here. No one wants to spend money putting out 4K content until there's enough significant demand for it, and that means 4K sets showing up in homes. But 4K sets are a tough sell if there's nothing to watch on them except regular HD content. Which means we've been in this weird in-between time, waiting for significant numbers of people to make a relatively illogical decision to buy an extra-expensive TV that will only look marginally better than their old one for the next year or two.
That's really dumb.
Hey, let's be careful with our mean words! Still, you've got a point. The current situation is a little silly. But 4K is legitimately awesome. And we're going to get there. We went through a similar transition a few years back with the move to HD (which came complete with the HD-DVD/Blu-ray format war and massive marketplace confusion) a few years back. Luckily that transition was eased a bit by the simultaneous move to the flatscreen form factor and a significant jump in screen sizes.
What kind of cables will I need for 4K?
The two standard cables you're most likely to use are either a standard HDMI or if you're connecting a PC to a Ultra HD monitor, DisplayPort.
HDMI cables now come in two flavors: 1.4 and 2.0. HDMI 1.4 cables are the super inexpensive kind found at the dollar bin of your local electronics retailer. They're cheap and can output a 3820x2160-resolution at 30 frames per second. HDMI 2.0 is the latest spec and can output video at Ultra HD resolution at 60 frames per second. (But more on that below!)
The other type of cable you can use is DisplayPort. DisplayPort carries 4K image and audio signal from most high-end graphics cards to monitors without any noticeable artifacts or delays.
So should I buy a 4K set now or should I wait?
It depends. If you want the absolute best TV you can get right now and don't mind paying a premium for it, it's a 4K set. If you're buying from one of the top tier manufacturers, you're going to get a good product that's reasonably future-proofed. As we said before, the sets look great. However, don't expect to be watching most of your video content in 4K for another two to three years. And make sure any set you buy has HDMI 2.0 ports (the first wave of 4K TVs used the previous HDMI 1.4 standard).
On the other hand, if you're price sensitive or want to wait until the content side of the equation is a bit more solved, it absolutely makes sense to wait. You're not missing out on much at the moment. There are incredible values to be found in generously-sized 1080p sets right now. And 4K sets are only going to get cheaper.