Ask S&V

Passive vs. Active 3D

Scott Wilkinson  |  Jun 3, 2011

My fiance and I will be buying a house soon, and once we're moved in and settled, we are going to buy a new HDTV. Unlike Leo Laporte, we are BIG fans of 3DTV. I have been following 3D and the various incarnations of 3DTV over the years. Now that real 3DTV is here, we can't wait!

The tough part will be deciding between the active-shutter system and the passive-polarized system. I have been looking at active systems for over a year, and I saw my first passive system at Best Buy about a month ago. It was quite impressive.

Is there any risk of a format war between the passive and active systems? Does all 3D programming work on both active and passive systems?

Frank Ireland

All modern 3D programming, from Blu-rays to broadcast TV to video games, will work on all modern 3D displays, so there's no risk of another format war in that regard. Each type of 3D display accepts any modern 3D signal—frame-sequential Blu-ray or frame-compatible broadcast—and displays it according to its own technology.

As for which technology to get, current passive-polarized flat panels have a lot going for them—less-expensive and more-comfortable glasses and a generally brighter image. However, they have one serious drawback—each eye sees only half the available vertical resolution. Not only that, if you sit close enough for a fully immersive 3D experience, you can see thin, black horizontal lines in the image, and diagonal lines have obvious jaggies. Also, in some cases I've seen, the set filters the high-frequency vertical information to cut the resolution in half for each eye, but that filter also affects 2D content, degrading the picture quality.

Okay, there is another drawback of current passive 3D flat panels—a very limited vertical viewing angle. If your eyes are much above or below the screen, you will see a lot of crosstalk, otherwise known as ghosting. So watching 3D while lying on the floor isn't possible.

Active-shutter systems are often dimmer, and the glasses are more expensive and heavier, but each eye sees full 1080p resolution, and there's no high-frequency filtering. Plus, the vertical viewing angle is much wider than on current passive sets.

The best of both worlds will be introduced by Samsung next year when it launches its new "active/passive" 3D TVs, which include an active polarization-switching layer in front of the screen. It uses passive glasses, but each eye sees full 1080p resolution. For more on this, see my blog about it here. I don't yet know about the vertical viewing angle on these sets.

If you have an A/V question, please send it to askscottwilkinson@gmail.com.

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