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日本Lenovo Yoga Book 9 (13IRU8) review – behold the king of all 2-in-1 laptops is here!
Display quality, Health impact (PWM), Sound
Lenovo Yoga Book 9 (13IRU8) is equipped with two OLED touchscreen panels, model numbers Samsung ATNA33AA02-0 for the main one and ATNA33AA06-0 for the second display. They both come with a 60Hz refresh rate. Their diagonal is 13.3″ (33.8 cm), and the resolution – 2880 x 1800p. The panels support the Lenovo Digital Pen 3 stylus. Additionally, the screen ratio is 16:10, the pixel density – 255 ppi, and their pitch – 0.1 x 0.1 mm. The screen can be considered Retina when viewed from at least 34 cm (from this distance, the average human eye can’t see the individual pixels).
Viewing angles are good. We offer images at different angles to evaluate the quality.
Also, a video with locked focus and exposure.
The two displays are almost identical, below you can read info regarding the main panel (the top one). The maximum measured brightness is 371 nits (cd/m2) in the middle of the screen (HDR off) and 372 nits (cd/m2) average across the surface with a maximum deviation of only 2%. The Correlated Color Temperature on a white screen and at maximum brightness is 6250K (average).
In the illustration below you can see how the display performs from a uniformity perspective. The illustration below shows how matters are for operational brightness levels (approximately 140 nits).
Values of dE2000 over 4.0 should not occur, and this parameter is one of the first you should check if you intend to use the laptop for color-sensitive work (a maximum tolerance of 2.0 ). The contrast ratio of OLED panels is practically infinite, due to their ability to turn off black pixels entirely.
To make sure we are on the same page, we would like to give you a little introduction to the sRGB color gamut and the Adobe RGB. To start, there’s the CIE 1976 Uniform Chromaticity Diagram that represents the visible specter of colors by the human eye, giving you a better perception of the color gamut coverage and the color accuracy.
Inside the black triangle, you will see the standard color gamut (sRGB) that is being used by millions of people on HDTV and on the web. As for the Adobe RGB, this is used in professional cameras, monitors, etc for printing. Basically, colors inside the black triangle are used by everyone and this is the essential part of the color quality and color accuracy of a mainstream notebook.
Still, we’ve included other color spaces like the famous DCI-P3 standard used by movie studios, as well as the digital UHD Rec.2020 standard. Rec.2020, however, is still a thing of the future and it’s difficult for today’s displays to cover that well. We’ve also included the so-called Michael Pointer gamut, or Pointer’s gamut, which represents the colors that naturally occur around us every day.
The yellow dotted line shows Lenovo Yoga Book 9 (13IRU8)’s color gamut coverage.
Its display covers 100% of the sRGB/ITU-R BT.709 (web/HDTV standard) in CIE1976, and 100% of DCI-P3, ensuring a super vibrant and attractive picture.
We tested the accuracy of the display with 24 commonly used colors like light and dark human skin, blue sky, green grass, orange, etc.
Below you can compare the scores of the Lenovo Yoga Book 9 (13IRU8) with the default settings – HDR off, and the one with our Gaming and Web design profile with the P3-D65 color space.
The next figure shows how well the display is able to reproduce really dark parts of an image, which is essential when watching movies or playing games in low ambient light.
The left side of the image represents the display with stock settings, while the right one is with the “Gaming and Web Design” profile activated. On the horizontal axis, you will find the grayscale, and on the vertical axis – the luminance of the display. On the two graphs below you can easily check for yourself how your display handles the darkest nuances but keep in mind that this also depends on the settings of your current display, the calibration, the viewing angle, and the surrounding light conditions.
Response time (Gaming capabilities)
We test the reaction time of the pixels with the usual “black-to-white” and “white-to-black” method from 10% to 90% and vice versa.
We recorded Fall Time + Rise Time = 5 ms.
After that, we test the reaction time of the pixels with the usual “Gray-to-Gray” method from 50% White to 80% White and vice versa between 10% and 90% of the amplitude.
Health Impact: PWM (Screen flickering)
Pulse-width modulation (PWM) is an easy way to control monitor brightness. When you lower the brightness, the light intensity of the display is not lowered, but instead turned off and on by the electronics with a frequency indistinguishable to the human eye. In these light impulses, the light/no-light time ratio varies, while brightness remains unchanged, which is harmful to your eyes. You can read more about that in our dedicated article on PWM.
Lenovo Yoga Book 9 (13IRU8)’s display uses PWM with a low frequency up to 100 nits. Above that, we see slightly weaker pulsations.
Health Impact: Blue light emissions
Installing our Health-Guard profile not only eliminates PWM but also reduces the harmful Blue Light emissions while keeping the colors of the screen perceptually accurate. If you’re not familiar with the Blue light, the TL;DR version is – emissions that negatively affect your eyes, skin, and your whole body. You can find more information about that in our dedicated article on Blue Light.
Health Impact: Gloss-level measurement
Glossy-coated displays are sometimes inconvenient in high ambient light conditions. We show the level of reflection on the screen for the respective laptop when the display is turned off and the measurement angle is 60° (in this case, the result is 144 GU for the main display and 142 GU for the second panel).
Sound
Lenovo Yoga Book 9 (13IRU8)’s Bowers & Wilkins speakers produce a sound of very good quality. Its low, mid, and high tones are clear of deviations.
