What is 3D TV and why should I care?

Updated November 21, 2011 6:18 AM PST
promo image 3D TV is back and like it or not, it's here to stay. Unlike "old" 3D with flimsy cardboard glasses and colored filters, today's version is high-definition, full-color and can bring home the same depth you've experienced in modern 3D theaters. Our guide takes you in-depth too, with advice on the what to expect from the "new" 3D TV.
What is 3D TV and why should I care?

3D TV compatibility is a new feature on higher-end LED, LCD, and plasma TVs released since 2010. It allows those TVs to display 3D content with the right accessories--namely 3D glasses and a 3D source. The main reason to care, if you're shopping for a new flat-panel TV, is because you might enjoy the effect enough to prefer it to normal 2D HDTV when watching movies and special events. With that in mind, here are a few basic points about 3D TV

All 3D TVs are first and foremost 2D TVs.

All 3D TVs will display current 2D high-def and standard-def content with no problem and no glasses required, and their 2D picture quality is not affected in any negative way we've noticed by their 3D capabilities. In fact, for the foreseeable future we expect most 3D TVs to spend most of their time showing 2D video.

That's why we prefer to think of 3D compatibility as "just another feature," like Internet streaming or a fancy remote control. You can take it or leave it, but for most TV shoppers it's not the most important feature on a modern television.

How 3D TV works.

A screen showing 3D content displays two separate images of the same scene simultaneously, one intended for the viewer's right eye and one for the left eye. When viewed without the aid of 3D glasses, the two full-size images appear intermixed with one another, fuzzy and basically unwatchable. When viewers don the glasses, they perceive these two images as a single 3D image, a process known as "fusing." The system relies on a phenomenon of visual perception called stereopsis, so it's not "true" 3D like real life or a hologram.

To view 3D on a 3D TV, you need 3D glasses, a 3D source device and 3D video content.

Despite the launch of glasses-free 3D products like the Nintendo 3DS, HTC Evo 3D and Toshiba Qosmio F755-3D290--and breathless reports by bloggers--we think an affordable, practical 3D TV that doesn't require glasses is at least five years away. For now, every viewer of a 3D TV needs to wear a pair of special glasses to see the 3D effect.

In addition to a new TV and glasses, you'll also need a 3D source, typically a 3D-capable Blu-ray player or cable/satellite/Internet video box. You'll also need the 3D version of the Blu-ray disc, or be watching a 3D program on a 3D channel or streaming service. (While some 3D TVs offer 2D-to-3D conversion, the process isn't really good enough to compete with native 3D content.)

New 3D TVs have 3D quality comparable to a theater.

3D TVs released since 2010 can display high-resolution, color-correct 3D images, which blows away the old "anaglyph" method using red-and-blue filtered glasses. The biggest differences between theatrical 3D and 3D TV in the home are the size of the screen and the distance you sit from it. If you enjoy 3D theatrical presentations, you're a prime candidate for caring about 3D in the home.

Not everyone can see 3D, and sometimes 3D causes discomfort.

Between 5 percent and 10 percent of Americans suffer from "stereo blindness." They often have good depth perception--which relies on more than just stereopsis--but cannot perceive the depth dimension of 3D video presentations.

By the same token, some 3D presentations can cause eye fatigue, headaches or other discomfort in some viewers, particularly over long periods of time. In CNET's experience, and in the opinions of most experts we've consulted, the main cause of eye fatigue isn't the 3D technology itself; it's badly produced 3D content.

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