4K/Ultra HD TVs
Next Generation HD TVs
Ultra HD TVs haven't really made it to the consumer market yet, but they dominate trade shows for the home theater and consumer electronics industries. The designation of "Ultra" HD includes anything over 1080p. 4K is the next generation, though some concept 8K televisions have been built. 4K TVs are double the horizontal resolution of a 1920 x 1080 HDTV. The actual size of most 4K TVs is 3840 x 2160, though the 3840 pixels are close enough to 4000 that it's rounded to make the name easy to remember.
4K: How much difference does it make?
Many consumers are dazzled by the picture quality of large 1080p HDTVs. 1920 x 1080 sounds like a lot of pixels, until you compare it to digital cameras. A 1920 x 1080 screen has 2073600 pixels, or 2.07 megapixels. Cheap, tiny phone cameras have eight to 12 megapixels, and nice point-and-shoot cameras have even more. So why do TVs have such low pixel count? For one thing, a TV has to display a frame approximately 24 times a second. So even though a 2 MP image isn't that big, storing 24 of them per second adds up pretty quickly. So storage and processing limitations are reasons we don't have higher quality videos.
Another reason is that you don't exactly need more pixels. Many computers come with monitors smaller than 20" that have a 1920 x 1080 resolution. Imagine purchasing a 20" computer with the same number of pixels as your 55" HDTV. Won't the TV look horrible? A little trigonometry will lead us to an answer. Most people sit pretty close to their computer screen, but much further from their TV. When you sit just over a foot away from your 20" computer screen, it takes up a large portion of your field of view. When you sit 10' away from your TV, however, it looks comparatively small. So even though TVs have relatively few pixels, they still look good.
4K: Unnecessary, but nice
Of course, the fact that 1080p HD TVs look good enough doesn't mean that we don't need higher resolution. For certain screen sizes and viewing distances, the extra pixels make a difference. The detail of 4K pictures is stunning and crystal clear, and makes incredible home theaters. Many movies are already being made in 4K, though few are published in that size. Having a 4K Ultra HD TV will allow you access to the best content possible, and it will also be more future-proof than a 1080 HDTV. Existing interfaces like HDMI 2.0 area already fast enough for 4K, and fast computers can handle displaying 4K movies. Most 4K TVs are too expensive for the average consumer, but as they get cheaper, it will be a worthwhile investment.