Smart TV Buying Guide: LED, OLED and 4K Compared

A smart tv buying guide starts with one rule: pick the screen and size first, then check the apps. Most shoppers in 2018 will do well with a 4K LED set that has HDR and the streaming apps they use. OLED gives the best picture but costs more.

Smart TVs connect to the internet. They play video apps, so you may not need a separate box. Here is what to check before you buy.

LED, OLED and what the names mean

Most TVs sold today are LCD screens lit from behind by LEDs. Shops call them LED TVs. A light at the back shines through a layer of pixels. Cheaper sets put the lights at the edge. Better sets place them behind the whole screen and can dim zones to make blacks look darker.

OLED works another way. Each pixel makes its own light and there is no backlight. A pixel that is off gives no light, so black looks truly black and contrast is very high. Sony designed a tiny 11-inch OLED TV, the XEL-1, back in 2007. Large OLED sets are newer and usually cost more than LED sets of the same size.

OLED screens can be more prone to burn-in than LCD screens. This means a still image shown for a very long time may leave a faint ghost. If you leave a news channel logo on for many hours a day, think about that. For mixed viewing, most people will not notice it.

The simple pick: choose LED for value and bright rooms. Choose OLED for movies in a dim room and when your budget allows.

Sources: Wikipedia, "OLED" (per-pixel light, burn-in risk), https://en.wikipedia.org/wiki/OLED; Wikipedia, "Sony XEL-1" (11-inch screen, designed in 2007), https://en.wikipedia.org/wiki/Sony_XEL-1

What 4K really means

In 2012 the Consumer Electronics Association said that TVs sold as "Ultra High Definition" must have at least 3,840 pixels across and 2,160 pixels down. That is four times the pixels of a Full HD (1080p) screen. Most people just say 4K.

The same rule says the set needs a digital input that can take a native 3840 x 2160 signal. In short, a real Ultra HD TV should be able to show 4K from a source without shrinking it first.

Is 4K worth it? On a small screen you sit far from, it is hard to see the gain. On larger screens it shows finer detail. Also, many mid and high range sets in shops are 4K, so you may end up with one anyway. Remember that your cable box, disc player or app also has to send 4K. Many channels still show in HD, and the TV will scale them up.

Sources: Consumer Electronics Association Ultra HD definition (October 2012), as summarized at https://en.wikipedia.org/wiki/Ultra-high-definition_television

HDR: brighter highlights, richer color

HDR stands for high dynamic range. It lets a picture show brighter whites, darker blacks and more color between them. A sunset or a car headlight looks more like real life.

In August 2015 the Consumer Electronics Association announced HDR10, an open standard for HDR video. It uses 10-bit color and a wide color range, and it adds data that tells the TV how bright the scene should be. Look for the "HDR10" label on the box.

Not all HDR is equal. A bright set with good local dimming shows HDR well. A cheap set may accept an HDR signal but look little better than normal. If you can, compare two sets in the shop with the same HDR clip.

Sources: Wikipedia, "HDR10" (announced August 27, 2015; 10-bit, SMPTE ST 2084), https://en.wikipedia.org/wiki/HDR10

Check apps and ports

The "smart" part is the software. Check that the TV has the apps you watch, such as YouTube and Netflix, and a way to add more. Ask how long the maker updates the software. Menus on some brands are slow, so try the remote in the shop.

If the apps feel poor, you can add a small streaming stick or box later. That is cheaper than a new TV. Keep this in mind when you compare prices.

Count the HDMI ports. You may want one each for a game console, a cable box and a soundbar. For 4K HDR from a console or player, look for HDMI ports that support it, since not every port on every set does. Check the box or manual.

Sound is often weak on thin TVs. A soundbar is a common fix. Budget a little extra for it.

Pick a size for your room

Bigger is not always better. Measure the distance from your sofa to the wall. Sit where you can see the whole picture without turning your head. A 4K set lets you sit closer than Full HD, since the extra pixels keep the picture sharp. Check this in a shop by standing at the distance of your sofa.

Measure the space too. Include the stand, or the wall mount if you plan one. Check the weight and the mount holes before you buy a bracket.

Think about light. A bright living room with big windows favors a brighter LED set with a low glare screen. A dark room favors OLED.

Quick checklist before you pay

Set a budget. Pick a size for your room. Choose LED or OLED. Look for 4K and HDR10 if you plan to watch movies. Confirm the apps and HDMI ports. Ask about the warranty and where repairs are done.

Last, see the set on in a shop if you can. Showroom settings are very bright, so ask the seller to switch to a movie or standard mode. That shows how the TV will look at home.

Sources: Sections above.

Sources

• Wikipedia, OLED: https://en.wikipedia.org/wiki/OLED
• Wikipedia, Ultra-high-definition television: https://en.wikipedia.org/wiki/Ultra-high-definition_television
• Wikipedia, HDR10: https://en.wikipedia.org/wiki/HDR10
• Wikipedia, Sony XEL-1: https://en.wikipedia.org/wiki/Sony_XEL-1