tv

A Sceptic's Guide to Buying (or Not Buying) a 4K TV

By Adam Clark Estes on at

Should you buy a 4K TV yet? With Black Friday in sight and Boxing Day sales on the semi-distant horizon, that is a question lots of people will be asking this year.

There are now loads of 4K TVs on the market, and they’re finally affordable in the eyes of many. Plus, importantly, 4K content is becoming easier to find. However, depending on the size of your living room and the demands of your eyeballs, you might get more for your money with an advanced Full HD 1080p model.

I’ve been doing research for a new TV of my own of late, and along the way I’ve picked up a few tips that make sense of the chaos of information out there. We’re in this together.

Don’t Buy it Because it’s Cheap

Shopping for a television is like shopping for a car: expensive and time-consuming. Sales can be enticing, especially around this time of year, but don’t settle for a TV just because it’s cheap. You might get a lemon. A massive, 55-inch lemon. No one wants that.

So, a TV should be considered as an investment. Something to put a little extra money into for the sake of how long it will be with you. There are limits, though. Tempting as it may be to spend thousands on some jacked up curved OLED screen bursting at the seams with smart features, at the end of the day any relatively new LED LCD screen will get you from the beginning to the end of your favourite film.

And in a sea of jargon and acronyms like HDR, Ultra HD and “expanding the colour gamut”, you should really just focus on the basics – resolution, size, and quality – when you’re trying to pick your new TV out of the sea of nicely priced LED screens on the market today.

Resolution is Overrated

Looking for the highest resolution screen is not the trick to buying the best TV. What you really want is the right resolution for you and your space. You might not actually require a 4K TV, regardless of a sale price (I would make a terrible salesman).

A television earns its 4K Ultra High Definition designation if the screen is 3,840 pixels wide and 2,160 pixels high. (4K is also known as 2160p.) That means there are four times as many pixels on the screen as a Full HD 1080p television. None of that matters if you’re going to be sitting more than about three metres from the screen, however, since the human eye is literally incapable of distinguishing the difference in resolution from that distance.

So, the extra pixels in a 4K TV only offer better resolution if the screen is large (upwards of 60 inches) or if you sit really close to the TV (say, 1.5 metres or closer) which makes for a difficult proposition when shopping for a new TV, since many of the cheapest 4K screens are in the 50-inch range.

At that size, it’s negligible whether the improved resolution will matter. To be sure, you should get out a measuring tape and check out this guide and this calculator to find out if you’d even notice the sharper picture in your living room.

The resolution question is not a new one. Back when I bought my 720p TV, I worked out that the lower resolution would look the same from where I was sitting as the more expensive 1080p options. It's worth taking the time to figure it out, with tools such as those to which I just linked, before parting with your money.

Picture Quality is Underrated

We haven’t arrived at the total 4K takeover yet, but we’re getting closer. The market-shift is creating a familiar problem, where TV companies want you to buy a new 4K TV so they’re phasing out the older 1080p TVs. (This happened with 720p TVs a few years ago.) Within a year or two, upgrading your telly might mean picking a 4K TV whether you like it or not, as Full HDs get given the boot.

Regardless of how many pixels you squeeze into the screen, picture quality can vary widely based on three factors: backlighting, refresh rate, and contrast ratio.

Backlighting

Let’s begin with backlighting. The vast majority of TVs on the market right now are LCD TVs that use LEDs for backlighting. They’re generally just known as LED TVs, not to be confused with the prohibitively expensive (but usually excellent) OLED TVs. (Plasma TVs don’t need backlights, but they’re also more or less extinct.)

Many lower-priced LED TVs are edge-lit, meaning the LEDs are located on the sides of the screen. Others are properly back-lit (so, from behind the screen), giving the TV better local dimming features. Local dimming allows certain clusters of LEDs to light up when the picture is brighter in certain spots. This works differently depending on the type of backlighting. Local dimming on edge-lit TVs is usually limited to columns of light, while back-lit TVs can light up very specific sections of the screen, a setup which is known as “full-array local dimming”. The number of zones will vary by model, but full-array local dimming is what you want to look for.

Refresh Rate

Now, let’s talk motion. A screen’s refresh rate refers to the number of times the picture updates on the screen per second. This specification is measured in Hertz (Hz) and will largely determine how the TV deals with motion. Thus, 60Hz means the screen draws 60 images per second. Higher refresh rates mean more updates and, therefore, smoother motion.

TVs in most countries require by broadcasting standards a refresh rate of at least 60Hz. However, you’ll see 4K TVs with “effective refresh rates” of 120Hz, 240Hz, or higher. That’s because various manufacturers use computer tricks to cut down on motion blur. This can produce what is known in some circles as the soap opera effect, which makes some content be too smooth. So be sure to find the TV’s “actual refresh rate”. (CNET even made a handy guide for the 2015 models.) Realistically speaking, you should look for a TV with an actual refresh rate of 120Hz.

Contrast Ratio

Here’s where scientific measurements for screen quality can become pseudo-scientific. The term 'contrast ratio' refers to the difference between the blackest black and the whitest white on the screen. Since this affects every colour in between those monochrome ends of the spectrum, the screen’s contrast ratio plays a major role in picture quality. The very best TVs will produce really dark blacks and super bright whites but, crucially, there’s no real standard for measuring contrast ratio.

This is why you want to see your TV before you buy. While certain factors like full-array local dimming will improve the screen’s contrast ratio, there’s no silver bullet to perfect settings. Be mindful of manufacturers' claims and keep in mind that the screen in the store might not be calibrated properly. If you’re eager for a in-depth technical explanation of how contrast ratio works, try this video.

Don’t Buy it Because it’s 4K

Semi-confusing terms and specifications aside, I need to reiterate my original point: just because a TV has 4K resolution, it doesn’t automatically mean it's a good TV. Resolution is one of many specs, and as discussed, at certain distances you might not even notice the difference.

There’s another wrinkle worth considering as well. If you plan on streaming movies and shows to your TV over Wi-Fi, you’re going to need a pretty zippy connection to make 4K content do anything but stutter and die on screen. Netflix, for instance, requires 25Mbps. That kind of speed is pretty standard if you’re hardwired into an ethernet connection, but Wi-Fi tends to be slower. Even if your connection is fast enough for 4K streaming, however, the image quality might still be degraded. You can tweak the settings, but you’ll still need to buy or download the Ultra HD file to ensure you’re getting the quality you paid for.

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Hopefully this all provides some ammunition for when you go to Currys and the sales assistants start their stock patter. Even if you do eventually buy online, it really is worth seeing your prospective screen in person and, with this advice in mind, go with what feels right for you, your pocket, and the space in which the TV will live.

Image by Sam Woolley


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