What is 3D television?

We last examined the phenomenon of 3D films and TV last year. At that point the new crop of 3D films had begun to appear, while 3D TV sets seemed a long way off.

The 3D films have now come and gone, and the first 3D television sets are on sale. Even television channels are trumpeting all the programmes they’re going to be showing in 3D. But has anything really changed and is the world ready for 3D TV?

How does it work?
The 3D image produced on a TV or cinema screen is obviously not three-dimensional in the way an object in front of us is. Instead, the screen uses technology to trick our eyes and brain into thinking there is a three-dimensional image.

The last time cinema and TV companies tried to introduce 3D it was with coloured glasses (usually with one lens red and one lens blue) that not only looked silly, but distorted the colours that appeared on screen.

Newer 3D technology uses polarised glasses, which look a little like normal sunglasses, with darkened lenses. If you have watched a recent 3D film in the cinema you will have been issued with a pair of ‘passive’ polarised glasses which are lightweight and cheap.

Televisions designed to produce 3D at home instead use ‘active shutter’ glasses that are heavier and more expensive. The screen sends a signal to the glasses which indicates to them how they show the 3D image to the wearer’s eyes.

For more information, see Computeractive's feature on how 3D TV and movies work.

What’s available?
The last time we looked at the technology there wasn’t really any home equipment available that would produce 3D images, and the new wave of 3D films hadn’t hit the big time. But late last year James Cameron’s Avatar was released. It was the first film designed to be shot using 3D cameras and was a box-office success, although critical reception was more muted.

Other films followed, either shot in 3D or in a conventional two-dimensional format and then converted to 3D afterwards. Converted films invariably don’t look as good as those shot for 3D in the first place.

The football World Cup held in South Africa earlier this year was also shown in 3D by satellite broadcasters, though not by Sky in the UK. Sky is showing Premier League matches in 3D in some pubs.

While 3D films aren’t being issued on DVD, some are being released on Blu-ray discs, such as the animated film Cloudy With A Chance Of Meatballs. These will also play on non-3D equipment.

Computer and console games have also started to appear in 3D. If your PC has an Nvidia graphics card you can add the Nvidia 3D Vision kit to watch in 3D (though you will still need a suitable TV or projector too). Sony has also made 3D available as a downloadable upgrade to its Playstation 3 console.