Seeing a 4K TV (with fourfold HD resolution) is a revelation. In a video of a cityscape that Samsung showed at a press event earlier this month, individual windows in many of the buildings were visible, as were individual people walking in and out of the skyscrapers. On an 8-million-pixel screen, the grid structure disappears (unless you get very close), making the screen look as clear as a photograph, but with motion.
However, the world that TV makers show on their 4K screens is largely an illusion — made possible with a few select clips shot on high-end movie cameras.
Price is the obvious reason to not get a 4K TV (so named because the screens are about 4,000 pixels across). It typically costs at least twice as much as an otherwise equally tricked-out HDTV (high-quality panel, online capability of the same size). But assuming money were no object, or that the cost suddenly plummeted (not so far-fetched, as smaller companies are already slashing prices), there are still four reasons to wait before you buy a 4K TV.
Little 4K video to watch
There is no Blu-ray disc, streaming video service, TV channel or even affordable camcorder that supports the 3,840-by-2,160-pixel resolution of 4K video. That's a good first reason to wait on this technology, and it could be a long wait.
In the meantime, TV companies are making a smattering of 4K content available on hard-drive-based players. Sony sells its 4K Ultra HD Media Player, complete with 10 movies on its hard drive, for $700. And Sony promises to have 100 videos available for download (certainly not streaming, given the size) to the player by the end of the year. That's a lot of money to pay for a TV that can show only a handful of movies.
Samsung plans to introduce a similar hard-drive device in the coming weeks.
Little benefit for regular HD content
In the meantime, 4K TVs can scale any HD video up by guessing at additional detail to fill in the extra pixels (as happens when you play an old-school DVD on an HDTV). The results are pretty good on some sets, such as Sharp's 69.5-inch (1.8 meters) AQUOS Ultra HD LED TV (listing for $8,000), which is certified by the labs at THX for its upscaling quality. But getting closer to a 4K TV, as the smaller pixels allow you to do, also reveals the grainy look of upscaled video.
Even with upscaled video, you might be able to comfortably sit closer to the screen than you would with an HD set, but maybe not close enough to make it worthwhile. Standards body the International Telecommunications Union recommends sitting at least 1.5 times the height of the screen away from a 4K TV (so as not to see distracting pixels) and three times the screen's height away from an HDTV.
For a 55-inch (1.4 m) TV, like the entry-level models from Sony and Samsung, that comes out to a little more than 3 feet (0.9 m) for 4K, or close to 7 feet (2.1 m) for HD. If you're not going to sit closer than 7 feet away, you're not going to get your money's worth. Samsung, for example, just began selling a 55-inch 4K model for $5,600. Its top-of-the-line 55-inch HDTV costs $2,800 (and it has other 55-inch models that are well below that price).
4K video can be choppy
The small selection of 4K video that is available won't appear at top quality, because the latest HDMI connections (version 1.4) delivering video to the TV can't handle all the data. The signal going into most HDTVs, such as from a cable box or a Blu-ray player, is at 60 frames per second. But the only way today's HDMI connections can carry data with four times as many pixels is to cut the frame rate in half. At 30 fps, video may not look as smooth.
4K video color is lacking
The other compromise is in color detail. With the bandwidth limitations, HDMI 1.4 can carry 4K signals with only enough data for 8 bits (256 shades) for each of the red, green and blue components of a pixel. Those primary colors can combine to produce a spectrum of about 16.7 million shades of color. That may sound good, but today's LCD panels can display at least 10 bits (about 1 billion shades) of color — so this high-resolution video will appear with a comparatively low amount of color nuance.
However, fixes are in the works. The new version of HDMI, expected to be called HDMI 2.0 and expected to have twice the bandwidth, could result in 4K video at a rate of 60 frames per second. Nonetheless, the color palette will likely still suffer until further upgrades come. But that hasn’t been officially announced, nor has whether or not it will support higher color quality.
The rumor among experts (nothing is official yet) is that HDMI 2.0 (or whatever name it takes) is coming soon. But there is no word on what "soon" is.
The prospect of a new HDMI standard is cold comfort for people who buy today's sets with the current HDMI connection, though some companies are planning for updates. All of Samsung's 4K TVs, for example, have an external box that takes the video inputs and handles some of the video processing. As input standards improve, owners can buy new boxes that support them.
Still, it's a weak sales pitch to ask people to spend at least twice as much for a TV that shows a small amount of video that is a bit choppy and lacks color nuance, only to pay more money to fix it when the technology improves. And by that time, the 4K TVs on sale may be a lot cheaper anyway.