Results: Display Measurements
The first screen measurements we take are brightness. While the rest of our display measurements, along with our battery testing, is done with the screen set to a standardized light output of 200 nits in order to make device comparison possible, it’s also important to know what your screen is capable of. We record the luminance output of each device using a full white pattern, with the device’s brightness slider set to both minimum and maximum values.
The Tegra Note’s maximum brightness level comes in right around 420 nits, a solid number that should make the tablet quite legible even in daylight. With basically the same maximum brightness as Sony's Xperia Z1, but with half the minimum reading, the Tegra Note should provide better contrast.
But before we get to the contrast ratio, we have to calibrate the brightness slider to within one percent of our target 200 nits. While we’re here, might as well check the calibrated black level, or the luminance output of a full black pattern when full white has been standardized.
The Tegra Note places just ahead of the Xperia Z1 once again, though by a much higher margin due to the Sony smartphone’s high minimum brightness. This is good showing for the Note.
Now onto contrast ratio, or white pattern versus black.
Nvidia’s tablet reads a contrast ratio of approximately 680.5:1, which is a fair score. It’s a tad under last year’s Nexus 7, though as predicted, far better than Sony’s Xperia Z1 despite the two devices having the same maximum brightness.
Color temperature is a measurement in Kelvin which is used to describe how “warm” a given display is. These are colors derived from the CCT or correlated color temperature. All of the displays tested are in the cool range (basically any temperature above 4000 Kelvin), but the following chart should give some indication of how they tend toward one end or another of the CCT scale.
As has been the case since the first iPhone, the iPhone 5s sits at the upper end of the cool spectrum with its whites tending to a cool blue hue. The Xperia Z1 and Tegra Note aren’t far behind either. In fact, out of all devices tested only the Samsung Galaxy Note 10.1 shows any major variance away from intensely blue hues and is more like a traditional PC monitor (most sit at 6500 Kelvin by default).
A gamma curve of 2.2, no more, no less is what we optimally want to see.
Once again, Apple Retina Display proves to be the best, with an approximate gamma of 2.19! Overshooting the 2.2 target, we have the current Nexus 7 and Galaxy Note 10.1” devices. Back on the lower side of the target we have the Tegra Note at just under 2.1, a quite respectable score, especially compared to the Tegre 3-bearing Nexus 7 (2012) and the abnormal display of the Sony Xperia Z1.
Our volume measurements are compared against both the sRGB and AdobeRGB color gamuts. A reading of 100% on sRGB and 72% on AdobeRGB is the optimal reading for viewing the vast majority of consumer digital content.
The Retina display of the iPhone 5s runs the closest to the optimal reading, followed closely by the current Nexus 7. The Sony Xperia Z1 overshoots the target, possibly leading to an image with an unintended blue/green tint. The Samsung Galaxy Note 10.1” 2014 Edition is next at an average reading of 85/60. The Tegra Note has the second-worst showing out of today’s comparison devices, followed only by last year’s Nexus 7. At just 74.7 percent of sRGB and 51.5 percent of AdobeRGB, the Note’s screen is closer to that of a cheap laptop screen or desktop monitor than what we’re becoming used to in gadget displays, one of the weaker points of this product.
Overall, the Tegra Note’s screen is OK, but the display on the new Nexus 7 is far superior, and the price difference is just $30.