It may not have taken the world by storm quite like the upgrade to high definition did, but 3D TV still has the power to amaze, especially the first time you try it out. The technology has fast become a standard feature on high-end TVs and we've even started to see budget 3D sets appearing on the market.
There are two systems currently used to produce 3D images -- 'active' and 'passive'. The main difference is the glasses.
Active screens require specs with a battery-powered liquid crystal shutter system that turns on and off in time with a sync signal from the TV. This produces the 3D effect. Passive goggles, on the other hand, are not powered. Instead, they use polarised lenses that work in conjunction with a filter on the front of the screen.
LG developed the passive 3D system on its own and currently all passive 3D TVs use LG panels. Unsurprisingly, all of LG's LED TVs have passive technology, but now some other manufacturers are building passive 3D TVs using the South Korean company's panels. These include Toshiba, Philips, Cello, and more recently, Panasonic.
However, Toshiba, Philips and Panasonic also produce active 3D TVs, while Samsung and Sony exclusively use active technology in their sets. Because of the way plasma TVs produce images, all plasma tellies -- even LG's models -- employ active rather than passive tech.
Both systems have strengths and weaknesses. The major advantage of the passive system is the glasses, which are extremely cheap. They only cost around £2 each, while active specs can set you back as much as £100 a pair. This makes passive 3D TVs ideal for enjoying 3D movies or broadcasts with the whole family or a big group of friends.
The low price also means you don't need to worry about them breaking as the replacement costs are very low. This is an important consideration if you have young children, especially as the expensive active specs can be a tad fragile.
Passive 3D sets also tend not to have an issue with cross-talk -- image ghosting on the edges of objects -- as long as you don't view the screen from a vertical angle of more than 15 degrees. The passive glasses are comfortable to wear because they're extremely light and they don't flicker, due to the lack of a shuttering system.
The downside of passive sets is they don't deliver a Full HD image when working in 3D. The passive filter on the front of the screen sends alternate lines in the image to each eye. Consequently, passive 3D images have half the horizontal resolution of active systems. In reality, it looks more like two-thirds the resolution of a Full HD image because of the way our brains process visual information. But you'll still see some jagged lines on the edges of objects now and again. This tends to be more obvious on TVs with large screens of 50 inches and above.
The advantage of TVs that use active 3D technology is they deliver a Full HD image to each eye so 3D pictures look crisper than those on passive displays. The difference isn't always that noticeable on smaller 3D screens, but with 50+ inches, the benefit is clearer as you don't get those tell-tale jagged edges of passive sets.
Active 3D TVs have some disadvantages too, not least the aforementioned price of the glasses. For this reason, many budget active 3D sets don't actually come with specs in the box -- you have to purchase them as an optional extra.
The shuttering system used on active glasses can cause flicker, which some people find fatiguing, especially when watching long 3D movies. They're generally heavier and bulkier than passive specs and so are less comfortable to wear. Some cheaper active 3D TVs can suffer from cross-talk, although the latest generation generally avoid this.
Below, I've rounded up some of my favourite TVs that will propel you into the third dimension.