Display

As we briefly discussed in our look at the specifications, the Galaxy S6 line introduces a newer generation of AMOLED displays, which is said to increase maximum luminance to 600 nits. Samsung claims that this was achieved with the use of new materials, which is likely necessary in order to sustain power efficiency improvements. It doesn't seem that AMOLED is uniquely suited to high resolution, but rather that Samsung Display Corp. is managing to dramatically improve how they make AMOLED displays with every year that offset power consumption increases from higher resolution displays.

To find out how Samsung did, we use SpectraCal's CalMAN 5 Ultimate, in addition to X-Rite's i1Pro2 Basic to characterize displays as accurately as possible.

Display - Max Brightness

From the results Samsung's claims of a 600 nit display are valid in this case, which is a 100% APL white display. It's important to note that achieving this requires the use of auto-brightness, and that manual brightness is limited to a much lower brightness to reduce power usage, here the S6 sees similar maximum brightness as the S5. The S6 edge disappointingly only achieves 272 nits in this mode, a rather low value. I saw color balance shift dramatically in auto-boost mode, which suggests that this operating mode is likely less efficient than manual brightness. As an explanation, we've seen that colors are controlled in AMOLED by voltage while brightness is controlled by PWM (pulse width modulation). As with most recent AMOLED displays, there's no DC bias to the pixels so the contrast really is infinite instead of just a very large number when displaying black.

Galaxy S6

Galaxy S6 edge

Display - White Point

Display - Grayscale Accuracy

Moving on to grayscale, we can see that Samsung has done a pretty good job of controlling the white point and gamma across the saturation sweep, even if green is slightly dominant in both displays. We can also see that there is variation across displays as the S6 edge is closer to neutral while the S6 sample tends a bit warmer.


Galaxy S6


Galaxy S6 Edge

Display - Saturation Accuracy

In the saturation sweep, both displays do an incredible job. I really don't have anything else to say here, because there's really no way to improve on the level of calibration Samsung has done on this display. Unless Samsung calibrates every single display in production, which is wildly impractical and effectively impossible to do, this is as good as it gets for a mass-produced device. Improving past this point will also be incredibly difficult to perceive, which means there's no real reason to go any further.


Galaxy S6


Galaxy S6 edge

Display - GMB Accuracy

In the Gretag MacBeth ColorChecker, we can get an idea for overall color accuracy, which paints a picture similar to the saturation test. The only real problem I've noticed with these displays are the viewing angles, which can produce color shifting when the display is tilted. This is a bit of an issue on the edge variant as I can see that the edges of the display appear somewhat green when viewed head on, but otherwise there are no real issues to be seen here.

Overall, from a color standpoint it’s looking like Samsung has made one of the best displays available on the market today. Color accuracy is at the point where it’s pretty safe to say that the calibration doesn’t have clear color errors, and the peak brightness of the display is incredibly high. The 1440p resolution helps to compensate for the PenTile subpixel layout so in practice it’s effectively impossible to make out any pixels or the subpixel pattern. The contrast remains infinite as with most modern AMOLED displays, and overall it’s really hard to find any issue with the Galaxy S6’s display at first.

However while the S6 edge seems to be without any issues, the S6 does have some odd display issues that can be seen in direct sunlight as seen in the photo above. To be clear about this the photo above is a simple white screen, which should make the image completely homogeneous but instead there are two visible vertical lines and another jagged horizontal line that appear across the display. Inspection under a light microscope doesn’t really reveal what’s causing this, but the defect is quite visible in practice as seen in the photo above. I suspect that defects are rare, and in any condition other than direct sunlight I can’t see this visual problem.

While trying to see what this kind of defect looked like under a microscope, I also went ahead and took some photos of the subpixel pattern. As far as I can tell, it looks like the green subpixels have a bit more variance than what we’re used to as they tend towards oblong shapes rather than circles, which is likely due to the much tighter pixel density. It seems that this variance may cause some color shifting in certain units, which seems to remain a potential problem with Samsung's AMOLED displays. The pixel fill factor still remains surprisingly low when compared to LCDs, which usually have much higher active area. Due to the subpixel arrangement and some other differences in the display design, color shifting also remains higher than one would expect from LCD displays that are found in phones like the iPhone 6.

The final test that I managed to run on the Galaxy S6 is the brightness vs APL test, which shows the advantage of AMOLED’s emissive nature as it can dynamically increase brightness if the entire display isn’t showing a white screen. As a result, this means that in low APL scenarios like dark movie scenes and app themes it’s possible to see a maximum brightness closer to 700 nits or higher. However, in practice the display’s practical brightness is closer to 600 nits.

Overall, the display is still one of the best on the market, but I would be a bit concerned about fill factor for VR applications as that was a problem on the Note 4. Issues like purple smearing have been resolved, but there are still some problems with the display such as color shifting with changes to viewing angles and some variability in display quality from unit to unit. With this generation I suspect Samsung is either meeting or exceeding the best LCDs in quality, and with the next generation of AMOLED it’s likely that high end smartphones will have to migrate to AMOLED to remain competitive.

Battery Life and Charge Time System Performance
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  • Richa - Friday, May 15, 2015 - link

    Am from India - Bangalore. I bought Samsung S6 edge 64 GB on 12th April 2015 and got to know battery is discharging rapidly within first week of use. I spoke to customer support and sent it for service center. Service center person and his manager said phone does not have any problem and returned same defect phone without fixing. Samsung is least bothered about their customers and service center guys are too unprofessional. Please help me what can be done. Battery back up is less than 3-4 hours.

    Samsung has the worst customer service. First they sell you defective pieces which starts showing problem within a week of purchase and then they will ask you to visit the service center 3-4 times a month just because their technical team is not strong enuff to recognizee the problem. Samsung doesnt value customer time money ... it has just some stupid people sitting at the call center whose work is to fool you and simply waste your time but wont provide genuine service or product .Samsung is the other name of Customer Harassment. My personal Experience which I am going through these days.
    Reply
  • techconc - Tuesday, May 19, 2015 - link

    @Richa:
    You sound surprised. Why? Is there anything in your experience history with Samsung or even stories of their customer service that leads you to believe this is an anomaly? Your experience sounds pretty consistent with my experience with them.
    Reply
  • An Droid - Monday, May 18, 2015 - link

    Try reading the article again. Maybe you will then grasp the advantages of UFS over eMMC. If you still do not understand it, look at the graphs (the pictures). Reply
  • schilling - Wednesday, May 20, 2015 - link

    Can someone explain why the video bit rate is so high? It is common for 1080P30 H.264 video to be in the 3-5Mbps range. I get the idea of increasing bit rates to improve quality, but 17Mbps seems ridiculous. I've seen many studies that clearly show that 1080P30 H.264 quality improves very slowly for bit rates above 5Mpbs. Netflix streams 1080P30 in the 1-2Mbps range; and yes their are artifacts, but this is 17-8x higher! The only logical explanation is that Samsung Exynos 7 is taking radical short-cuts in their H.264 CODEC. For example, using only I-Frames, or keeping a very small motion search area.
    Does anyone have insight to this? Has anyone viewed their stream with a CODEC analysis tool like StreamEye?
    Why is Samsung's bit-rate so ridiculously high?
    Reply
  • The Rogue Tomato - Saturday, May 23, 2015 - link

    Removable battery and no microSD card isn't a big deal anymore. You can get a great quick-charge-capable $20 10,000 mah external battery now that you can use with your own phone, or your girlfriend/wife/boyfriend/husband's phone, too. Just today I wanted to be able to have an extra power source for my phone and my wife's phone. A $20 thingy would be ideal for that.

    And although I have one with my Note 4, I don't see the point of having a microSD slot anymore. I'd rather have the faster internal storage. It's not like I'm going to carry around 100 movies on my phone. If I really want movies, I can put them on a cheap thumb drive and use OTG.
    Reply
  • bloosted - Tuesday, July 7, 2015 - link

    You guys should revisit this and do an in-depth on the different camera sensors. Now that some time has passed, it's become very clear that the isocell sensors that some gs6 owners randomly end up with are greatly inferior to the sony sensors that you originally tested. Interestingly, it seems most (if not all) of the online reviews of the s6 and s6 edge were done on phones containing the fantastic sony sensor, which received near universal praise. Tom's hardware just did a review of the two sensors and found the isocell sensor greatly lacking. Reply

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