Can You Really Tell the Difference Between 4K and 8K?

Some time in the past I got here to really feel, in a really literal method, the pace of semi-recent technological progress. My roommate—a gamer—had gotten it into his head, presumably by way of another gamer, that ‘90s video games look best when played on ‘90s televisions. This led him to secure one on Craigslist, which led in turn to my assisting him in hauling it up the stairs. And it was just, let me tell you, the heaviest fucking thing. I could not believe how heavy that TV was.

In the 25+ years between that TV’s debut and its eventual arrival in my lounge, televisions have modified a complete bunch. Now they’re all flat, and never significantly heavy. As you may anticipate, the display know-how has additionally improved dramatically. Some pricier fashions provide 8K UHD decision, double the earlier normal of 4K. Is the image on these 8K TVs actually twice nearly as good as 4K? At a sure level, are there diminishing returns with regards to picture high quality? For this week’s Giz Asks, we reached out to quite a lot of consultants to search out out.

Professor, Psychology, University of California Berkeley, whose analysis focuses on visible notion, consideration and reminiscence

The apparent reply is that it will depend on (1) how giant your tv is and (2) how distant you’re watching it from. The advantages of 8K shall be most simply seen on a really giant TV seen from a brief distance. They shall be nearly invisible on a small TV seen from distant. The identical is true, comparatively talking, of present 4K TVs vs. 2K TVs (1920 × 1080 pixels, aka “1080p”)—they work higher with bigger TVs seen at shorter distances.

Professor, Vision and Computational Neuroscience, MIT

Let’s sort out this with some technical element: Normal visible acuity (what we frequently seek advice from as 20/20 imaginative and prescient) corresponds to having the ability to resolve two dots separated by ‘1 minute of arc.’ What does this imply? One’s thumb, at arm’s size, is about two levels extensive, and a level has 60 minutes. This signifies that if you happen to have been to attract 120 evenly spaced dots in a line throughout the width of your thumb, then at arm’s size you’ll simply barely be capable to see the person dots. At any higher viewing distance, or with any extra dots, you’ll be unable to inform the distinction between the dotted line and a steady one. If we translate this calculation to a TV, it seems that for a display 60″ wide viewed from five feet away, the limit of our resolution is 4K. At this distance, we would be able to tell the difference between HD and 4K, but any increase beyond 4K (say, to 8K) would not be noticeable. We would need to get right up close to the TV (quite an unnatural thing to do) to tell apart a 4K screen from an 8K one. So, unless one is planning on having a really huge screen, or is planning on watching TV from very close up, 4K is plenty. The step up to 8K (from 4K) will likely be unnoticeable in most living room setups.

Assistant Professor, Optometry & Vision Science, University of California, Berkeley

We’ve all experienced situations that push the limits of what our eyes can see. Maybe you’ve struggled to read the tiny text on a food label or strained to recognize the face of a friend in a crowd. While the human visual system is remarkable, it has an array of limits that render some aspects of the world effectively invisible. When it comes to display design, understanding these limits is essential for understanding whether one display will look better than another.

The difference between an 8K television and previous generation displays comes down to an increase in the number of pixels. In modern television displays, individual tiny pixels are arrayed side-by-side in a grid. Each pixel in this grid emits a spot of color, which together make up the images you see on your television. When you watch your favorite show, you’d like to see these images in high detail without being distracted by also seeing the individual pixels. That is, you want the images to be vivid but the pixels to be invisible.

Will an 8K television deliver improvements on these conditions? It depends on a lot of things, like the display contrast, how big each pixel is, and how far you tend to view from—it even depends on the type of image that you’re looking at and how fast that image is changing. For example, if you view a television from far enough away that each pixel is smaller than your visual system can resolve, the pixels will be invisible whether the display is 4K, 8K, or 100K pixels wide. If you pull out some measuring tape and remember your trigonometry, you can easily calculate the number of pixels per visual degree for your own viewing set up. If you are already above 60 pixels per degree, you’re not likely to see improvement with an 8K television of the same size (for reference, one visual degree is about the width of your thumb held at arm’s length). On the other hand, a display with more pixels can in principle enable you to see more details over a wider field of view if the panel is bigger or if you want to view from close up. This, of course, all assumes the original recording also has 8K resolution or higher.

Increasing pixel count can certainly result in benefits, but the details of how you view, what you view, and where you view from will ultimately determine what is a visible benefit to you.

Martin S. Banks

Professor, Optometry, Vision Science, Neuroscience, & Psychology, University of California, Berkeley

There are recommendations for the resolutions of TV displays, cell phones, etc. These recommendations typically boil down to one thing, which is that the pixel should create a visual angle of “1 minute of arc” or smaller. “Minute of arc” is a technical term, and, despite “minute,” it doesn’t involve time: only space is involved. Think of one minute of arc as a little cone of light coming towards the eye. That’s the pixel on the TV screen, and it comes to a point at your eye. One minute of arc is the angle that the cone makes from your eye to the pixel. An HD TV has 2,000 pixels from left to right, a UHD TV has 4,000, and here we’re talking about 8,000. A lot of people in my field think the “one minute of arc” recommendation is flawed—that it should be smaller.

Viewing distance also comes into the equation here. Skipping over some math, it works out that if you have a 2K TV (HD), and it’s 3 feet tall, you need to sit 9.3 away or closer to appreciate the resolution; if you’re 20 feet away, there’s no way you can tell the difference between your TV and one that has a somewhat smaller number of pixels. If you have a 3-foot-tall 4K TV, you’d have to be about 4.5 feet away or closer to tell the difference, and nobody sits that close. Go all the way up to 8K, and now you’d have to be two feet from your three-foot-television to appreciate it. You’d have to be a very rare kind of viewer to want to take advantage of that.

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