Why scientists say there's 'no point' forking out for a 4K or 8K TV
A fancy new ultra–high–definition television might seem like a great investment.
But scientists say that you might be wasting your hard–earned cash.
According to a new study from the University of Cambridge and Meta Reality Labs, there is 'no point' for most people to fork out for a 4K or 8K screen.
This is because these top–of–the–line screens have a higher resolution than the human eye.
Much like our TV or phone screens, the eye has a resolution limit, meaning we can only see so many pixels in a given area.
That means, at a certain point, increasing the quality of your TV won't actually improve how the screen looks to the average viewer.
The exact resolution is affected by several factors, such as the size of the TV, how far away it is, and how dark the room is.
But, for an average UK living room with 2.5 metres between the TV and the sofa, a 44–inch 4K or 8K screen offers no benefits over a worse Quad HD TV of the same size.
Scientists say that there is 'no point' for most people to splash out on a fancy 4K or 8K television, since these screens have a higher resolution than the human eye (stock image)
Television screens usually describe the quality of the picture by talking about 'resolution', which is the number of pixels that are used to make the display.
4K simply refers to any screen that has around 4,000 pixels on the horizontal axis, no matter how large the screen is or how dense these pixels are.
Likewise, an 8K screen will have roughly 8,000 pixels on its horizontal axis, with most measuring 7,680 pixels by 4,320 pixels – approximately 33 million pixels in total.
The idea is that the more pixels you have, the more details you can render in the image, and the clearer the display will be.
The latest 8K televisions can cost hundreds of pounds more than an older high–definition model, so it's important for consumers to know if this is really worth it.
Despite the huge advances in display technology, there hasn't been any serious research into whether the human eye could even detect these improvements.
Co–author Professor Rafał Mantiuk says: 'If you have more pixels in your display, it's less efficient, it costs more and it requires more processing power to drive it.
'So we wanted to know the point at which it makes no sense to further improve the resolution of the display.'
This table shows the maximum resolution that is worth paying for, depending on the size of the screen and the distance from the sofa. Each coloured square represents the resolution that is beyond the abilities of 95 per cent of people to see any improvements
In their study, published in the journal Nature Communications, the researchers tested participants 'pixels per degree' (PPD), a measure of how many pixels can fit into a one–degree slice of your vision.
Participants placed their heads on a chin rest and looked at patterns with very fine gradations in shades of grey or in colour.
The screen was slowly moved towards and away from the participant as they were asked whether they could see the lines in the image.
These tests were repeated in the centre of the field of view and in the peripheral vision.
The researchers found that the eye's resolution was a bit higher than had previously been thought, but still much lower than what would justify using a more expensive screen.
First author Dr Maliha Ashraf, of the University of Cambridge, told Daily Mail: 'For most people, it's not worth upgrading beyond 4K; once you sit at a normal distance away, your eyes can't actually see the extra detail that 8K provides.
'A good 4K TV is already sharper than what 95% of people can resolve. So, unless you sit very close or have a very large screen, you won't notice any improvement.'
The eye's resolution is even lower for bright colours, especially in peripheral vision, since our brains don't actually have the capacity to process details in colour very well.
Researchers used a sliding television to work out how many pixels per degree of vision the human eye was able to see. While results vary between people, this shows that ultra–high–definition displays are wasted on most of the population
The average resolution in the centre of the field of view was 94 pixels per degree for greyscale images, 89 for red and green images, and just 52 for yellow and violet.
That means there simply isn't much point splashing out for a more impressive screen unless the TV is really huge or you plan on sitting very close.
Dr Ashraf points out that a higher resolution can be useful for professional monitors where users are often sitting very close and looking at small details.
For example, if you're sitting less than a metre away from your monitor, you should be able to see the full potential of an 8K display even on quite a small screen.
But, beyond two metres, not even a 100–inch screen is big enough for you to see the difference between a 4K and an 8K screen.
If you're sitting three metres away from the television, you'll need a whopping 60–inch screen to get the most out of a 4K display.
Visual resolution does vary across the population, and some people can see finer detail than others.
However, the researchers' calculations allow for how those limits change across the population.
For most people and houses, a Quad HD display with 2560 x 1440 pixels (pictured) is more than sufficient. Improving the resolution any further generally won't make the image appear any clearer
That means you can work out what resolution would be right for 50 per cent, 75 per cent, or 95 per cent of the population.
For example, if you're sitting two metres from a 40–inch Quad HD display, only 30 per cent of people would be able to notice the difference between this and a better display.
But if you move back to 2.5 metres, not even someone with perfect vision could tell the difference.
To learn more about what TV is right for you, the researchers have created an interactive calculator.
Simply enter the size of your room, the size of your TV, and the display resolution you want to use to work out what proportion of people would notice the improvement.
