In an 8K vs. 4K double-blind study, Warner Bros. together with Pixar, Amazon Prime Video, LG, and the American Society of Cinematographers (ASC) tried to solve the question of the required resolution. We wouldn’t have expected the results otherwise.
The structure of the study 8K vs 4K
In order to achieve the most meaningful results possible, the test set-up had to be well planned and strictly regulated. The whole conditions in detail can be found on techhive.com. We have summarized them for you shortly. For simplification we also use the terms “8K” (actually 8192×4320) and “4K” (actually 4096×2160), although if you want to stay correct it should actually be called UHD (3840×2160) and UHD-2 (7680×4320). But since even the TV manufacturers use 4K and 8K, we do the same in this article.
In order to find out how much added value the higher 8K resolution has, seven different clips were played on an 88 inch 8K LG OLED Z9. These clips had all been filmed in 8K (or better) or, in the case of the animated Pixar clips, rendered. In order to have the perfect comparison material in 4K, these clips were then scaled down to 4K and then scaled up to 8K again to avoid switching times or the like. The upscaling process, however, simply increased each pixel to 4 new pixels. So you have 4K material that is saved as 8K video.
The 7 8K clips
Of course, each of the companies involved wanted to contribute something. So there were two clips from “Dunkirk” by Warner Bros, one clip from “A Bug’s Life” and one from “Brave” by Pixar, two clips from “The Tick”, an Amazon Prime series, and one clip of nature shots by Stacey Spears. All clips use the HDR10 Media Profile - HDR with a color depth of 10 Bit in the Rec. 2020 colorspace codec and are very different in terms of average and maximum brightness of the scenes.
Implementation of the study
A total of 139 people took part in the study. Before the people saw the clips, their eyes were examined to make sure that the results had substance.
Short digression: To determine the visual acuity of the participants, the Snellen vision test was carried out. The result is always given in the form 20/x. The average value is 20/20, which means that from a distance of 20 feet one can see just as sharply as a person with normal vision from 20 feet away. 20/40 would mean that you see just as sharply from 20 feet as a person with normal vision at 40 feet, so your vision is worse. And 20/10 would mean you see just as sharply from 20 feet as a person with normal vision at 10 feet, so you see better.
The majority (61%) had 20/20 vision or better. Whereby the respective test results are also considered later in the evaluation.
Five people each watched the clips, with 2 people sitting 5 feet away from the TV and 3 people sitting 9 feet away.
There were 3 runs in which all clips were shown 4 times each. In two runs the resolution was always alternated between 4K and 8K. By chance the different resolutions got the letters “A” and “B” here. In the third run, as a control group, only the 4K material was played, but it was also alternately marked with the letters “A” and “B”.
The test persons should then indicate after the runs which material, “A” or “B”, was better. The possible answers were “much better”, “better”, “slightly better” and equal.
Results of the double-blind study
The results of the study show that the 8K clips were rated on average only as “marginally slightly better”. So most people did not notice any difference.
However, the results were also dependent on the clips. The biggest difference could be seen in the nature shots, although this difference is still very small.
If you look at only the 61% of the participants with at least average visual acuity, they described the 8K versions of “A Bug’s Life” and of the nature shots as slightly better than the total number of participants. But even these results are still very low.
Only if you only evaluate people who have a visual acuity of 20/10 and sat only 1.52m away from the 88 inch OLED, the results become clearer. At least “A Bug’s Life” and the nature shots (Who would have thought it?) could then be described as really better.
Significance of the results
However, there are also other results. For all the clips, except for the nature shots, the most common result was that the participants stated that both clips looked equally good. But even more blatantly, about a quarter of all statements were that the 4K material would look better than the 8K material. The reason for this is, according to the responsible person, that the majority of the participants must have guessed…
Meaning of the 8K vs 4K study
The crucial question is: What does this mean now??
The simple answer is that most people should not buy an 8K TV because of the resolution. Because the results only became clearer when people with above-average visual acuity sat only 1.52m away from an 88 inch TV. We have already written an article on the correct sitting distance and the viewing angle is between 20° and 40°. With 88 inches and only 1.52m distance, the viewing angle is no less than 65°, which would be far too much for most viewers.
So is 8K dead?
No, 8K will continue to exist and the TV manufacturers will also continue to bring more and more 8K TVs to the market for a lower and lower price. That’s what marketing is for.
However, most films or series will not be produced in 8K resolution, at least not every step of the production chain. This means that for 8K TVs it is important that they have a good 8K upscaling feature.
But the really important result is that the resolution is not the decisive factor when it comes to image quality. Because the other factors for a good picture are much more important. Therefore High Dynamic Range - image/video with more dynamic range (contrast range) is of much more importance. In the same way it is important that all the things we report on the individual TVs are right. In other words, that the characteristics such as contrast, brightness, colour space coverage and so on are on a good level. That’s why our tvfindr calculates the right TV not on the basis of resolution but on other test results. The resolution is also not included in our direct comparison.
This does not mean that an 8K TV is a bad choice, just that resolution should not be the deciding factor in most cases. For example, if you’re looking for an 88 inch TV with really impressive picture quality for home cinema, the LG OLED Z9 is an excellent choice, but for reasons other than resolution 😉
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