The ASUS ZenPad S (Z580CA) Review
by Brandon Chester on August 31, 2015 8:00 AM ESTDisplay: Stock Settings
I often say that a smartphone is just a display you interact with, which makes the need for a high quality screen paramount. This is even more true for tablets, which are quite literally large touchscreen displays that the user interacts with. With tablet displays having peaked in terms of resolution for the time being, manufacturers are now turning their attention toward color accuracy. Flagship devices like Samsung's Galaxy Tab S tablets and Apple's full sized iPads feature displays with an exceptional level of color accuracy, while smaller or less expensive tablets are more hit-and-miss.
Unsurprisingly, the ZenPad's display is very similar to that of the iPad Mini 2 as far as brightness, black level, and contrast are concerned. While Apple has decided to round 7.85" to 7.9", and ASUS has decided to round to 8.0", I'm fairly confident both devices are using the same LCD technology with different backlight arrays. It should be noted that while the contrast ratio is similar in our measurements, when there is ambient light there will be a much more significant drop in contrast on the iPad Mini 2 due to its unlaminated display.
Even if two devices use the same display panel, the color characteristics of each can vary significantly depending on the level of calibration, as well as the spectral range of the LED backlight used. Apple’s iPad Mini 2 achieves a level of greyscale accuracy where errors can only be seen in static content, and is good enough for editing photos and videos without concerns about the accuracy of the images. The ZenPad S doesn’t do as well, with a significant blue shift to most shades of grey. This is also reflected in the display’s high average white point of 7331K. While the ZenPad S doesn’t cost as much as an iPad Air 2 or a Galaxy Tab S2, the Z580CA’s price of $299 is exactly the same as the iPad Mini 2. With that in mind, it’s concerning to see such a gap between the greyscale performance of the ZenPad S and the iPad Mini 2.
Saturation accuracy on the ZenPad S is much lower than what could be achieved with more attention paid to the display’s calibration. With a DeltaE average of 6.2, the ZenPad S is actually less accurate with rendering primary and secondary colors than the iPad Mini 2, despite the latter having a backlight array that only allows for narrow coverage of the blue and red parts of the sRGB gamut. The spectral range of the LEDs in the ZenPad S almost covers the entire sRGB gamut, but the panel undershoots significantly with reds, overshoots with blue beyond 60% saturation, and has various levels of inaccuracy with yellow, cyan, and most of all, magenta. I was really excited to see that the ZenPad S doesn’t suffer from the narrow gamut of the iPad Mini 2, but I was let down when I realized that the accuracy of primary and secondary colors was actually worse than the iPad due to inadequate calibration.
Accurately reproducing color mixtures requires a reasonably accurate gamma, RGB balance for grey shades, and accurate saturations. Gamma on the ZenPad S is reasonably accurate for a mobile device, but the way the display tends toward blue coupled with the inaccurate saturations results in inaccurate color mixtures as well. The ZenPad’s average DeltaE of 5.55 doesn’t compare favorably with the iPad Mini 2’s DeltaE of 3.4 which is imperfect but still fairly accurate. The reason that the iPad Mini 2 ends up being more accurate is because while it cannot be accurate outside its native gamut, within the section of sRGB that it does cover it is very accurate.
As far as the default display configuration of the ZenPad S goes, I’m not exactly thrilled. While it does have a wider gamut than the iPad Mini 3, it ends up being less accurate in every respect due to issues with rendering primary and secondary colors, and a blue shift in the greyscale. Surprisingly, the ZenPad S having a fully laminated display has done nothing to reduce black levels and increase contrast ratio when compared to the non-laminated iPad Mini 2 display, which is an additional disappointment. However, ASUS does provide a few settings to tweak the display, and so hope is not lost.
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Shadow7037932 - Monday, August 31, 2015 - link
Man, that's disappointing. I was hoping more value like the Zenfone 2.MrSavage - Monday, August 31, 2015 - link
More value like what? Put a 16GB storage along with 1GB of RAM like the iPad mini 2 (as mentioned endlessly in this review) and don't you think it would cost less than $199? So then the Z580CA would be price around $199 or less, and the 2 year old iPad mini 2 would be $100 more. Oh yes, more value please. Afterall, let's compare apples with oranges. Zenfone 2 value? So a 8-inch display for a price similar to a 5.5-inch display device. Put stylus support into the Zenfone 2 and what would that cost?Kepe - Monday, August 31, 2015 - link
Does ASUS pay you to troll around here, praising the Zenpad and dissing everyone who finds the product a bit disappointing? Price doesn't matter at all if the product fails on too many categories that would have been rather easy to fix. This thing has too many software issues, such as artificially oversharpening everything on the display (makes small text hard to read for example), always on CABC and poor camera image processing.Cheap price alone isn't enough to justify the problems this thing has. You wouldn't buy a badly made and designed car even if it was 30% cheaper than the competing, well-made and thought of car.
Of course cheap price doesn't always mean something is bad. Look at OnePlus 1 and 2 and the new Moto X. They're half the price of the competition, but you couldn't tell that by the spec sheets or how they are made and what materials are used. Those are good examples of how to make a cheap product in an intelligent and thoughtful way.
MrSavage - Monday, August 31, 2015 - link
Hey friend. I think it's okay to challenge people or to question logic. You don't logically compare a smartphone with a tablet. Do you? I would expect a $100,000 car to be on a level playing field as a $20,000 car. I wouldn't compare the Z380CA to an iPad mini 2 because if you removed 3GB of RAM, put in a slower processor, and removed 32GB of storage then the Z580CA would be priced around $200 don't you think? Compare apples with apples is logical. You don't own one so I would suspect you don't have any credibility on what the Z580CA has or doesn't have. With a weak review, things can and should be corrected by people who know better in the comment section. You can always always always get more bang for your buck. Apple proves that. To me the failure is partially on Asus for sending an early review unit that OBVIOUSLY needed a firmware update prior to publisher, and beyond that, one key component the Z stylus isn't even available for those reviews. I'm expressing my opinion to clear up some of the ignorance out there.Kepe - Monday, August 31, 2015 - link
You are not making any sense at all. The iPad mini 2 and the Z580CA cost exactly the same amount of money: $299. That is why they can and should be compared. The iPad mini 2 is 2 years old, that's why it has less ram, storage, slower processor and such.Somewhere else in the comments you said people shouldn't compare the Z580CA to a Samsung tablet because it was $100 more expensive. Now you say people shouldn't compare devices that cost the same. What the heck are we supposed to compare, then? Two Z580CA's and look at them with a microscope to spot some differences in the surface texture and then compare them?
Besides, I haven't been comparing a tablet to a phone. The charts in the review have phones as well because they use the same SOCs (processors, GPUs).
The reason graphs and charts are used and detailed measurements are taken (display, performance, specs) is to remove objectivity from the results. Without them, every review would be like this:
"The display is ok I guess. There wasn't any significant UI lag. Gaming was ok. Weight is ok, not too heavy. Battery lasted for quite a while. It's an ok tablet I guess."
That kind of a review doesn't benefit anyone. The only way to properly decide which device is better at which thing is to measure those things, put them in a chart and compare them. As a reader, you should have the brain capacity to understand the price and other differences by yourself. We all know that the Zenpad reviewed here costs $299 and some other devices in the charts are more expensive and some are less expensive. It's up to the reader to decide what kind of price/performance he or she wants. It's the same thing with GPU reviews. The charts have old GPUs, new GPUs, cheap GPUs, expensive GPUs all in one. It isn't unfair, because everyone understands that the cheap ones won't be as fast as the new ones, and the expensive old ones won't be as fast as expensive new ones. You have to use your own brains when you're reading.
MrSavage - Monday, August 31, 2015 - link
I can appreciate what you're saying. I'm not trying to argue with you, only to discuss. Let me clarify. Similar price is fair, so long as the specs match up. The ipad mini 2 and Z580CA are total apples and oranges. It's not an equal value trade off at all. If you strip most of the things I mentioned, then you will have a true value comparison.The reason the new Samsung Tab S2 is worth comparing is because they are comparable spec wise, except for the storage and a bit of RAM. The value proposition of the Z580CA exceeds the negatives, but that's my opinion.
Charts and graphs have some value, so I'm not disregarding those entirely. Obviously anandtech is very reliant on their data and that's fine. Perhaps the audience reading the review will figure things out on their own, but it's a false assumption to assume that people understand the technicalities. I don't disagree that people need to use their brains when analyzing data or stats. Some stats however are statistically insignificant and that's why I take issue with some of those devices listed.
Those best review is one that looks realistically at the cost/value proposition. Everything out there sucks in the tablet category against the iPad Air 2. Beyond that, the review here of the display is sporadic and unclear. If it's software? If it was patched at some point during the review? That should not be made as an aside. It's not clear to me if the issues were resolved with the update and that essentially nullified most of the previous complaints being made about the display. Just not good enough in my books. Beyond that, it's never a good idea to trust one review and make a decision or judgement based on that.
BurntMyBacon - Wednesday, September 2, 2015 - link
Let me try to word it a different way. For the same price you get an extra 3GB of RAM, a faster processor, and an extra 32GB of storage. If those things are of highest importance to you, then this equates to more value. However, if your personal priorities dictate that use of iOS, Apple branding, build quality, display quality, etc. are more important, then perhaps you come to a different conclusion.LoganPowell - Friday, November 27, 2015 - link
Unfortunately Asus Zenpad Z580CA ranks rather poorly among top rankings (see ranking http://www.consumerrunner.com/top-10-best-tablets/ for example...)BurntMyBacon - Wednesday, September 2, 2015 - link
@Kepe: It doesn't matter if the iPad Mini 2 is two years old. That doesn't make it suddenly a better value. Either the price needs to drop accordingly, or a newer updated version needs to hit the market. Of course, you may find it a better value given other characteristics, but that depends on your priorities.Puck85 - Thursday, September 10, 2015 - link
serious question: what should I buy instead of this around this price range? Is there a better value out there I should consider?