There is a simple rule for TV screens: bigger is better, for most people. That is true no matter what the resolution. That is similar to HDTV: the screen aspect ratio is considered better by most people, irrespective of the higher resolution. That said, most people, watching a TV from a standard viewing distance, can perceive the difference between HDTV and NTSC, for example.
But it is possible to argue that, for many viewers, 4K will not bring benefits as obvious as did HDTV, unless screen sizes get much bigger, or people are willing to move their furniture much closer to the TV sets.
But higher-definition display formats always face a chicken-and-egg problem, in that, until content production catches up with the new higher-resolution formats, consumers might find only limited content available that actually takes advantage of the higher resolution. Think about older film or video content shot in the 4:3 aspect ratio, when modern displays use a 16:9 format.
Add to that the fact that linear or streaming video providers also have choices. They can deliver signals in standard or HDTV formats. Layer on 4K content and delivery formats and there is another layer of decisions to be made by video subscription services.
But even assuming there eventually is much more 4K content available to view, there will be other nuances for buyers of 4K and 8K displays. Human eyes and video resolution is a matter of physics.
Beyond a certain viewing distance, the human eye is unable to discriminate between content with 4K and HDTV resolution. A person with 20/20 vision sitting two feet from a screen (a PC screen, typically) can perceive the 4K resolution on a screen of 28 inches diagonal.
That should immediately tip you off to something important about TV screens. People do not sit two feet from their TVs. Six to eight feet is probably typical. When it comes to televisions touting new 4K technology, "a regular human isn't going to see a difference," said Raymond Soneira, head of display-testing firm DisplayMate Technologies.
To be sure, a 4K screen is capable of displaying four times the number of pixels as a 1080p screen. But the human eye is capable of seeing that many pixels depending on the size of the screen and where a person is sitting.
From a distance, it is virtually impossible for someone to tell the difference in quality between a 1080p and 4K screen. The advantage arguably is most clear on the largest TV screens, as those allow people to sit at a normal distance and still be close enough so that a person with good vision can perceive the improved resolution.
As a practical matter, recommends Sony, viewers should sit 1.5 times the vertical screen size of the TV, which is twice as close as people tend to sit when watching a standard HDTV screen. Buyers of the largest screens will have an easier time of the transition. But people buying smaller 4K TVs will have to scoot their couches up uncomfortably close to a 4K screen to perceive the enhanced definition.
People looking at a 55-inch screen must sit no further away than 3.3 feet to perceive the resolution, Sony says.
Others suggest an appropriate viewing distance for an HDTV screen of 55 inches is seven to 11.5 feet away. For a 4K screen, that distance drops to 4.5 to seven feet, according to electronic product retailer Crutchfield. Me, I’d go with Sony’s recommendations.
The point is that many buyers of 4K TVs will discover they really cannot perceive the difference from an HDTV screen, unless they are willing to move their furniture much closer to the TV than they are used to.