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本帖最后由 whindson 于 2018-10-17 16:45 编辑
国产电视中这机器算做得不错了，avforums给出了8/10的评价。
不过海信电视普遍问题还是色彩调教不行，bt709色域色准问题算小，校色后只有100%饱和度的六基色定点不准，HDR模式下就惨不忍睹了，色准偏的一塌糊涂。
Out of the Box Measurements As with all of Hisense's 2018 TVs, the U9A ships in its Standard picture setting, but after testing all five options (Vivid, Standard, Cinema Day, Cinema Night, and Sports), the most accurate modes are the two Cinema settings. For the purposes of testing, I predominantly used Cinema Night.
The out-of-the-box greyscale performance of the U9A was fairly good, although there was an excess of blue and a slight defect of red and green. That's unusual for the Warm colour temperature setting, where there's usually an excess of red instead. As a result of the excess blue, the DeltaEs (errors) were just over the visible threshold of three from 50 to 100IRE. However, the gamma curve was tracking my 2.4 target precisely, and overall this is a solid performance out of the box.
Hisense's less capable TVs have delivered very accurate colour gamut measurements in testing, mainly because they couldn't go any wider than Rec.709. That isn't the case with the U9A, which thanks to the use of quantum dots, has a very wide native colour gamut. As a result, the TV struggles to contain the colour gamut when trying to track Rec.709. This is particularly true at 100% of green, red, yellow and cyan, all of which are over-saturated, although the luminance measurements (not shown on the graph above) were fairly accurate. The tracking at 25, 50, and 75% is better, but Hisense needs to work on its colour accuracy when using quantum dot.
The out-of-the-box performance was good but the U9A struggled to contain its huge colour gamut
Calibrated Measurements The Hisense U9A has a solid selection of calibration features that includes a 2-point and a 20-point white balance control. In addition there's the option to choose different gamma settings, as well as calibrate the gamma curve on a more detailed basis. There's also a colour management system (CMS) with controls for luminance, hue and saturation.
I started by using the two-point white balance control to reduce the amount of blue energy and bring red and green up slightly. Immediately there was a big improvement in the greyscale, so all I needed to do was fine tune with the 20-point control. As you can see in the graph above, the U9A is delivering a reference greyscale and gamma performance after calibration, with all the errors below 0.5.
After calibrating the greyscale, the colour gamut was now more accurate and the colour temperature for white was smack in the middle of its target, rather than skewed towards blue. I then used the CMS to fine tune the accuracy of all three primary (red, green and blue) and secondary (cyan, magenta and yellow) colours at 25, 50, and 75%.
The result was a very accurate colour gamut up to 75%, but as you can see there is still over-saturation at 100% in many of the colours. However, you're rarely looking at a 100% saturated image, it tends to be in the 25 to 75% range, and so I consider the accuracy at those points more important. I could have used the CMS to make 100% more accurate but that would just mess up all the lower saturation points.
After calibration the greyscale and gamma were spot-on, but the colour accuracy needs some work
HDR Measurements The Hisense U9A supports HDR and the company actually quotes a peak brightness of 2,500nits. If that's true it would make the U9A the brightest of any TV I've tested. Hisense has generally been commendably honest in terms of its specs, so I was curious to see how the U9A measured in terms of peak brightness. When the TV detects an HDR signal it goes into the correct HDR mode to accommodate the PQ EOTF by changing the Gamma and putting the Backlight and Contrast controls up to 100, and the Local Dimming to High.
The U9A actually performed very well in my initial HDR tests, and using a 10% window I got a peak brightness of 2,777nits in Dynamic mode. That's almost the largest I've ever measured, although I did briefly get 3,000 nits from the Q9FN in testing. However that only lasted a second or two, whereas the U9A could consistently deliver numbers that high for a prolonged period of time. Since the local dimming was set to High, I measured the HDR black level at 0nits but more on that later.
In terms of a more accurate picture mode, I measured the Cinema Night mode at 2,450nits, which is almost exactly the same as the 2,500nits that Hisense quote in their specifications. I was also pleased to see that the tone-mapping on the U9A tracked the PQ EOTF very closely. There was a red push to whites in terms of the measurements, but this didn't appear to affect the overall image, and there was no clipping on 4,000nits content either.
If the U9A impressed in terms of greyscale, tone-mapping and peak brightness, it didn't fare so well when it came to colour accuracy. First of all the good news, thanks to the quantum dot technology used, the U9A measured 81% of Rec.2020, which is widest colour gamut that I've seen to date.
However, despite this, the U9A struggled to correctly track other colour spaces, so it only covered 95% of DCI-P3, when it should easily have hit 100%. It also struggled to correctly track DCI-P3 within Rec.2020, and, for reasons that I can't explain, it measured significantly less than DCI-P3 despite its huge native colour gamut.
Hisense clearly have some work to do when it comes to the colour temperature of white, which still uses the industry standard of D65 in HDR, and colour accuracy against DCI-P3 within Rec.2020.
Has brightest HDR and widest colour of any TV measured, but needs to effectively apply its attributes
avforums评测过的色域最广和亮度最高的电视，但实际表现有点对不起它的广色域和高亮度。
打个比方，海信把f1引擎装进了一辆汽车，但它的变速箱太烂了，导致实际跑的和比亚迪差不多
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发表于 2018-10-17 16:40
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