TV buying guide

Have a stroll around your local electronics superstore or browse the online shelves of internet retailers and you'll find a bewildering array of TVs on offer. Years ago, when there was only really a single type of TV technology -- CRT -- your main worry was what size of screen to buy. Now you need to choose between LCD, LED or plasma technology, decide what type of digital tuner it should have and weigh up the pros and cons of built-in Internet access and digital media playback.

If you haven't been keeping up with the latest developments in the world of TV, buying a new set can be a bewildering experience. This buyer's guide will arm you with all the knowledge you need to find the right TV at the right price. So let's get started by looking at the different TV technologies currently available.

Plasma

Plasma technology has a number of strengths. The inherent fast response times of plasma panels mean that they don't suffer form the motion blur that you often see on LCD and LED screens.

Plasmas tend to produce very deep black levels and softer, more natural looking colours, which makes them very popular among home cinema aficionados. It's probably closest to old CRT tube tellies in terms of the feel of its pictures (including colour temperature and contrast). If you mourn the loss of your old tube telly it might be the technology for you.

It's easier for companies to make larger-sized displays using plasma technology. Large screen plasmas are generally cheaper than large screen LCD or LED models, particularly in screen sizes of 50 inches or more. Conversely, the technology isn't suited to producing smaller screen sizes, so you'll rarely see a plasma display that's smaller than 42 inches.

Plasmas do have some disadvantages; a lot of glass is used in their construction so they're much heavier than LED counterparts. This can make wall mounting them tricky, especially on a partition wall.

The glass surface of the screen tends to reflect ambient light in the room. As a result, they're not necessarily the best option if your TV tends to get most use during the day in a bright room. Pictures from plasma screens tend to be less bright than those from LCD and LED displays, although manufacturers like Panasonic have upped the brightness levels on their plasmas significantly over the last couple of years.

The upshot is that plasmas are a great choice for those who want a big screen TV without doing massive damage to their wallet. An ability to produce smooth motion also makes them great for watching footie and their deep contrast levels and natural colours will endear them to keen movie watchers. Those with families that mostly watch telly during the day would be advised to explore LCD or LED sets. But if you opt for plasma, Panasonic's VT30 (pictured above) is currently one of the best TVs that money can buy.

LCD

The benefit of LCDs is that they produce very bright images with punchy colours. This makes them ideal for viewing in bright conditions, such as watching TV during the day. Unlike plasmas, these screens don't have a glass surface, so they're lighter and don't reflect as much ambient light in the room. The latter can be very important if your TV is positioned next to a window.

The technology can be used to build TVs in a broad range of sizes, from small 10-inch displays right up to more typical 42-inch TVs. However, plasma screens are still generally cheaper than LCD displays at larger screen sizes of 50 inches and above.

Nevertheless, LCD screens do have their downsides. Lesser quality LCD screens often suffer quite badly from motion blur; fast panning shots in football matches can look very blurry, for example. Also, cheaper sets can struggle to produce deep black levels, leading to darker scenes in movies taking on a cloudy or misty look.

Some displays suffer form poor viewing angles; colours can look either overly dark or washed out if you sit at an angle to the set. Nevertheless, manufacturers have made great strides in reducing these problems on most mid- and high-end sets, although these problems are still evident on some cheaper TVs.

It's true that many manufacturers are gradually replacing the LCD screens in their ranges with LED sets, but it's a mistake to think that LED TVs are automatically better than LCD modes. They're not, and we've often found that mid-range LCD TVs perform better than mid-range LED ones. Sony's excellent, low-cost KDL-40CX523 shows that there's plenty of life in LCD TVs.

Generally you'll get more bang for your buck by opting for an LCD display over an LED one. Extra features may include digital media playback and support for Internet TV content, as well as better picture processing features.

A good LCD set will perform well right across the board, both for watching TV during the day or settling down for a movie once the kids have gone to bed. However, be wary of bargain basement LCD models; it's on these sets that you're likely to see some of LCD's weaknesses such as motion blur and unruly, garish colours. These can make movies and TV shows look very plasticky and cartoon-ish. 

LED

Sweeping the TV market at the moment is light emitting diode (LED) technology. LED is really just an evolution of LCD. Both display types work in pretty much the same way using a backlight to illuminate liquid crystals that are sandwiched between two polarised glass layers. The difference is that instead of using florescent tubes as the backlight, these sets use rows or grids of LEDs.

These LEDs are either positioned behind the display (often referred to as direct LED backlighting), or at the edges, with a light diffuser to spread the light out evenly across the picture (usually known as edge LED backlighting).

LEDs are brighter than fluorescent tubes and use less power. LED backlighting can often (but not always) produce more even lighting across the surface of the display, reducing the patchiness that was sometimes seen on older LCD sets. The increased light output usually helps to boost brightness and the apparent intensity of onscreen colours, while improving contrast levels.

Another advantage is that LED sets can be made much thinner than either LCD or plasma displays, especially when edge backlighting is used. Some screens, such as Samsung's LED8000 range, have bezels that are as thin as 5mm.

Some LED sets have local dimming technology. This allows the LED lights in darker areas of the picture to be dimmed or turned off to increase black levels and overall contrast performance. The best results with local dimming are achieve when direct backlighting is used -- a grid of LED lights behind the screen. Local dimming is also possible using edge-mounted LED light although haloing is more of a problem.

What is haloing? It's best to explain it by means of a practical example. If you've got white text on a black background, instead of the black being universally dark, the area around the white text appears more grey than the rest of the black background. However, this effect isn't really all that noticeable on normal viewing material.

LED sets are generally more expensive than their LCD counterparts. You'll often find that plasmas are cheaper at the larger screen sizes. However, there's no denying the desirability of LED models. Some of them are almost impossibly slim with bezels that are well under 10mm thick. Also, their bright pictures help to combat the dimming effect of 3D glasses on 3D-compatible models.

High-definition

Pretty much all the TVs you'll find on sale today support high definition. The benefits of high-definition are plain to see, as HD images are much sharper. In fact, they're between two and five times as sharp as standard-definition pictures.

There are two types of HD screens: HD-ready models and Full-HD sets. HD-ready TVs generally support high-definition at a resolution of 720p (1,280x720 pixels); this means they can show images that are twice as sharp as standard-definition. Full-HD screens, on the other hand, support 1,080p (1,920x1,080) images, which are five times as sharp as standard definition images.

If you're opting for a larger screen of over 32 inches in size, then you're best going for a 1,080p screen. However, on 32-inch and smaller sets, the difference between 1,080p and 720p isn't all that noticeable when you're sitting at a normal viewing distance. So at these screen sizes, opting for an HD-ready model won't be a big compromise in terms of picture quality; plus you're likely to save money as 720p displays are usually cheaper.

Of course, to take advantage of high-definition, you need to feed your TV with a high-definition source. Consoles such as the Xbox 360 and Playstation 3 output video in high-definition; you can also watch movies in HD via Blu-ray discs played from a Blu-ray player.

If you want to watch television in high-definition, you'll need to either subscribe to high-definition services from pay TV providers such as Virgin Media and Sky, or alternatively buy a HD set-top box. Or buy a TV with a built-in HD tuner capable of receiving Freeview HD or Freesat HD services.

Freeview HD is available in most areas through a normal aerial, while Freesat HD is transmitted via satellite so you'll need a dish to be able to pick up the signals; an old Sky dish should work fine for reviewing Freesat HD channels.

All TVs upscale standard-definition channels to fill their HD screens, but this isn't the same as Full HD as the picture quality is nowhere near as crisp or as clean-looking.

Active or Passive 3D

Two competing 3D systems emerged. The first system is known as Active 3D and is available across a range of TVs including LCD, LED and plasma models, from manufacturers such as Panasonic, Sony and Samsung. Active 3D technology uses powered glasses with lenses that shutter on and off in time with the screen to deliver a Full-HD image to each eye.

The second method is known as Passive 3D. It's available on LCD and LED models, but not plasma displays. These TVs have polarising filters in front of the screen that work with passive glasses, similar to those used in 3D cinemas.

On passive 3D sets, only every second line in the Full HD image is shown to each eye, so the resolution is half of what you would get from an Active 3D system. However, because of the way our brains process images, in reality the effect looks closer to two-thirds of the Full-HD resolution.

LG is the main backer of Passive 3D technology and the system is used on all of its 3D LED and LCD screens. Toshiba has a select number of Passive 3D TVs in its line-up and British manufacturer Cello also produces a Passive 3D TV range. However, Active 3D technology is the only technology that works with plasma sets, so even LG's plasmas use Active 3D technology.

Active 3D glasses are very expensive, costing between £60 and £100. Because they include shuttering circuitry they can be quite bulky and heavy, making them slightly uncomfortable to wear. In contrast, Passive 3D glasses are much cheaper, typically costing around £1 or £2 per pair. They are as light as normal cheap plastic sunglasses. Furthermore, 3D images appear brighter because they don't dim the image as much as Passive 3D glasses.

Crosstalk is one problem that can affect 3D images on 3D TVs (example pictured). This is where you'll see a ghost image on the edges of objects in the near- and mid-distance on 3D pictures. It's caused by the stereoscopic image for one eye bleeding into the other, usually because the panel's response time isn't fast enough to quickly flick between the two distinct images for the left and right eyes.

Active 3D plasma displays and passive 3D LED and LCD sets don't usually suffer very much from this issue, but it has been a big problem on the first generation of Active 3D LCD and LED screens. That said, the latest generation of Active 3D LCD and LED displays have performed much better in this area.

Audio

Generally, you'll get the best sound quality from LCD TVs because their chassis are thicker. LED sets are often the worst audio performers because they're so slim, while plasmas vary in quality according to the thickness of their chassis and the placement of the speakers.

Some manufacturers are addressing the issue. For example, the current line-up of Panasonic's slim-line LEDs and plasma flare out at the bottom to accommodate larger speakers, while many of Philips' sets have a mini subwoofer on the rear to provide added bass-end punch.

Internet and digital media playback features

Of course, in the UK, the most popular Internet TV service is the BBC's excellent iPlayer offering, which lets you catch up on shows that you missed when they were originally broadcast. All the big manufacturers now support iPlayer on their connected TVs, including Samsung, Panasonic, LG, Toshiba and Sony.

Most manufacturers offer iPlayer support alongside a range of other services. These include the likes of YouTube and Dailymotion, movie-on-demand service such as LoveFilm and Acetrax, as well as TV news services like Euronews and Sky News.

Many sets also support Internet-connected apps. These range from simple news headline and weather forecast services, to apps that support social networking sites like Facebook and Twitter. Increasingly manufacturers are adding app stores that let you select extra apps and services to download to your TV. Most of these are currently free, but some are likely to incur charges in the future.

While there's no doubt that built-in support for iPlayer and some of the movie rental services is handy to have, many of the other apps score big on novelty factor and low on usefulness. It's worth bearing in mind that Internet services are available through a range of other products, such as many Blu-ray players and consoles like the PlayStation 3. So if your TV doesn't have onboard Internet features, you can add an external device later.

Many of today's mid- and high-end models also support playback of digital media files, such as photos, music tracks and videos. Usually these sets allow you to play media files either locally from hard drives or memory keys plugged-in to USB ports, or alternatively by streaming across a network from a PC or networked hard drive.

Format support varies quite considerably between different TVs and even among TVs from the same manufacturer. So, for example, while some models will happily play HD MKV files as well as Xvid and DivX videos, others will only support Xvid and DivX, but not MKV videos.

In fact, some models are so fussy that they'll play more formats locally via USB than they will stream across a network. So check format support carefully before buying your TV if media playback is important to you. Remember that most media streamers offer much broader format support than the majority of today's TVs and only cost around £100.

The value of Hertz

You'll see many of today's sets marketed as having 100Hz or higher processing. Manufacturers aren't very good at explaining what it does and how it can benefit a set's picture quality.

Pictures in the UK are delivered to our TVs at 50Hz. However, one of the inherent weaknesses of LCD and LED screens is motion blur. When the screen has to show lots of movement across the entire screen, such as a panning shoot following a racing car (see image), the picture can look quite blurred and smeary. In an attempt to avoid this, manufacturers have added clever circuitry to their TVs that add extra images into the video stream in an attempt to smooth out the motion. So, on a 100Hz TV the set adds in an extra frame between each frame. It's sort of a stepping stone between the preceding and following frames that fills in the motion gaps between the two. On 200Hz screens, double the number of frames are added in.

However, when you get to 400Hz screens, the processing remains at 200Hz, but the TV also strobes or blinks the backlight on and off very rapidly in time with the pictures -- so fast the human eye can't see any actual flickering; this creates an extra black, or dead, frame. It also helps to trick your eyes into believing that the motion on the screen is smoother than it is on the original video stream.

Not to be left out of the 100Hz marketing game, plasma manufacturers have started adding 600Hz badges to their screens. However, a 600Hz plasma isn't really processing in the way that LCD and LED screens do. It's simply a benefit of the technology. Plasmas have to constantly send a signal to each individual pixel to keep it lit on the screen -- they do this every 1/60th of a second. It's the reasons why plasmas are generally better at reproducing motion than LCD and LED screens.

With manufacturers pushing 100Hz and 200Hz on LCD and LED TVs, rather than say that plasmas didn't have this technology because they didn't need it, they simply added the 600Hz figure to make it look like it was comparable to other types of screens.

Buying your TV

Most people still buy their TV in-store, either from chains like Currys, Comet, Richer Sounds or smaller independent shops. The advantages are obvious: you get to see the TV in the flesh and get a much better idea of how the design will look in your home. You also get to try out stuff like the remote control and the TV's menu system.

If you're lucky, you may get a salesperson who is actually pretty knowledgeable about the products they're selling and can advise you on which type of set may best suit your needs.

If you're buying in-store then you'll generally get the best deals when TV ranges are end-of-line. Usually these sets are being phased out because the latest model has a slightly different specification, so retailers will sell off the remaining stock at a discount price. If you keep your eyes peeled you can pick up some real bargains.

It's also worth bearing in mind that some stores offer to price-match against their competitors and also sometimes offer extended warranties for free. For example, John Lewis has a price-matching policy and offers a free five-year warranty on all its TVs.

Increasingly, people are opting to buy their set online. Internet prices are often much more competitive than the prices you'll see in store. You can also easily compare prices across a range of retailers using price comparison sites.

It's worth remembering that since 31 October 2000, those who buy online, over the phone or through mail order are protected by the Distance Selling Regulations 2000. Perhaps the most important part of this legislation is that you are given a cooling-off period of seven working days, within which you can cancel your contract with the supplier and return your TV.

This is unconditional, so you don't have to give a reason for the return -- it can simply be that you've changed your mind or don't actually like the model that you've chosen. You will often have to give written notice that you want to cancel the contract, however, and you may have to cover the cost of actually returning the TV.

There's nothing stopping you from combining the two shopping experiences. Why not create a list of TVs you're interested in and check them out in store? Then once you've made your mind up, you can compare in-store and online prices using your smartphone and make a decision on which retailer will get your hard-earned cash.