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Originally Posted by peterv
Last year, Samsung came under a lot of heat for this feature from rival LG. This was for creating a very faint mosquito netting effect across the screen and for hurting the set’s ability to achieve the full contrast modulation (CM) measurement threshold for 8K resolution specified by several measurement standards organizations, including the Consumer Technology Association (CTA). We didn’t have the equipment necessary to measure CM (it’s a pretty esoteric issue) but Samsung supplied us with pixel grid magnification shots that the company said indicates the 2020 8K models are capable of presenting CM resolution that complies with the measurement standards for 8K resolution. Samsung did not supply us with an explanation for exactly what it has done in the 2020 models to achieve this change, but from an eye ball test, the resolution and color looked excellent and no visible mosquito netting effects were apparent in our samples of real world content.
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The main problem between LCD with QLED backlighting was at the time trying to increase the viewing angle so it wasn't as narrow as most LCD flat panels tested. This article discusses the problem of using VA Liquid crystal that Samsung was using. see
So, When is 8K not 8K - LG has a View! - DisplayDaily (8 months ago)
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Of course, the background to this was that LG is starting to talk about shipping an 8K OLED TV set and has to compete with Samsung, which has been trying to get the market hyped up about 8K for a couple of years for the reasons that I explained at the time. (8K is Closer than You Think) Unfortunately, as I have also written before, going to 8K means four times as many transistors between the light source and the viewer. Unless the panel is twice the diagonal (and four times the area), that means a lower aperture ratio and optical efficiency. (Samsung's Colour Performance Seems to Have Reduced with 8K)
That problem can be solved by boosting the power of the backlight, but then you get other challenges. As I wrote, Samsung already has to work hard to meet the EU Energy ratings. If you can afford a Samsung 8K QLED, you probably don't worry about the power bill, but those concerned with green issues will care about the high consumption.
However, to achieve the Level D rating, Samsung has had to make its colour filter slightly less aggressive, so the colour is not quite as good as its 4K QLED TVs were last year. At least, that's the reason that I'm speculating for the drop in performance - but several panel makers that I have spoken to have come to the same conclusion. It has also had to do some other things.
Now, the VA liquid crystal mode that Samsung and most others use for TV panels produces very good contrast when viewed square on, but the contrast performance and degrades quite quickly when you are off-axis and the colours shift. To fix this, VA panel makers divide up sub-pixels into multiple domains - typically at least four - each of which has the molecules slightly differently aligned, by electrical fields or by physical protrusions on the panel. This allows some 'averaging' and means more consistent performance. Samsung has done some amazing work to produce very good performance and uses, as I understand it, 8 sub-domains per sub-pixel, divided into two groups of four. Each of those groups has a slightly different gamma response to achieve the optimum overall effect.
Unfortunately, that kind of technique uses more transistors, which is just about acceptable on UltraHD/4K, but at 8K, these extra transistors would kill the energy efficiency, so Samsung has had to go back to four sub-domains, reducing viewing angle performance. To fix this, Samsung has employed a wide viewing angle film and that means good viewing angles, again. Sadly, that viewing angle film smears the pixels into each other, killing the resolution. Probably.
Normally, and according to the current ICDM measurement standard, the way to measure resolution is to display alternate lines of black and white pixels and measure the contrast between them. For text use, the contrast must be at least 50%, while for images it should be 25%. At IFA, LG was pointing out that the latest 8K QLED panels, with wide viewing angle film, don't do this - reaching around 12% to 18% depending on the size of the panel. LG has taken the question to two independent labs (Intertek and VDE) that have tested the panels and confirmed LG's view that they don't meet the ICDM definition of 8K resolution.
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Now given that Samsung buyers were usually using the 8K sets to upscale 4K or less content, it likely was not as apparent. Still if actually using native 8K content such as fine print where you have only two colors it would be a lot more obvious as a issue.
Whether Samsung has now rectified this issue with 2020 models and has met their goal of 50% min (CM) I don't recall it being discussed/debated online. ??
Obviously the sharpest images will occur on self emission based panels (microLed, and OLED) where OLED's were 90%. There is also the fact that OLEDs have good viewing angle of 65 degrees as a comparison.
Yes consumers will see Samsung 8k displays as a good buy, as Robert sells them, as they are more reasonable priced, but like everything thing out there is the good vs the bad.
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