The ASUS ZenPad S (Z580CA) Review
by Brandon Chester on August 31, 2015 8:00 AM ESTCamera
While most people will use either their smartphone or a dedicated camera for taking photos, a tablet can be used in a pinch. Some people even make their tablet their primary camera, whether it be because it's their only device, or because they prefer the larger viewfinder that a tablet offers. While many may still find the idea of taking photos with a tablet to be absurd, one need only look at the people around them to see that for one reason or another tablet photography has become a way that some users choose take photos.
The ZenPad S Z580C sports a 5MP rear-facing camera, and the Z580CA bumps that to an 8MP sensor. Since resolution is only one of many aspects of a device's camera system, I've included some more information about the ZenPad S Z580CA's cameras in the chart below
| ZenPad S (Z580CA) Camera Specifications | |
| Front Camera | 5MP (2592x1944) |
| Front Camera - Sensor | Omnivision OV5670 (1.12 µm, 1/5") |
| Front Camera - Max Aperture | F/2.4 |
| Rear Camera | 8MP (3280x2464) |
| Rear Camera - Sensor | Toshiba T4K35 (1.12 µm, 1/4") |
| Rear Camera - Focal Length | 3.0mm (28mm eff) |
| Rear Camera - Max Aperture | F/2.0 |
The ZenPad has a similar camera stack to the ZenFone 2. Toshiba's T4K35 sensor has a resolution of 8MP with 1.12 micron pixels, while the ZenFone 2 used T4K37 which had the same pixel size but a higher 13MP resolution. Lens aperture and focal length end up being the same as the ZenFone 2 as well.
To evaluate the still image quality of the ZenPad S I've taken photos of my standard photo scene during the day and at night, and compared the results to the other tablets that I have available for testing which includes the Nexus 9, the iPad Air 2, and the Dell Venue 10 7040.
It's clear that the ZenPad S suffers from the exact same processing issues as the ZenFone 2. There's far too much sharpening of the image as well aggressive noise reduction. This can be easily seen in any of the foliage in the frame, and in the lines separating the bricks of the school walls. There's also noise across the entire sky, despite this photo being taken with enough light for the camera to shoot at the base ISO of 50. The still image section of my ZenFone 2 review goes into more detail on these issues, and it's disappointing to see that none of them have been resolved. Relative to the other tablets in my comparison, I would have to say that the ZenPad S takes the lowest quality photos. The exposure and color accuracy is much higher than the Dell Venue 10, but the extreme oversharpening and heavy noise reduction makes the image look more like a painting than a photo.
In low light the ZenPad S continues to perform poorly. Low light scenes really make it clear how much of a photo's quality has to do with the quality of the image processing performed. Both the Nexus 9 and iPad Air 2 share a sensor size and resolution with the ZenPad S, and both actually have smaller apertures. Despite this, they both have a better exposure and a much greater level of detail than the ZenPad S. Unlike the day photo test, I would say that the ZenPad S did take a better photo than the Dell Venue 10, but only because I can't even begin to describe the problems with the Venue 10's photo.
Ultimately, the ZenPad S suffers from the exact same issue as the ZenFone 2, which is poor image processing. The color rendition and exposure of images taken during the day makes it clear that the camera has potential, but the numerous issues with the processing produces poor quality images.
WiFi Performance
Like the ZenFone 2, the ZenPad S Z580CA uses Broadcom's BCM4339 WiFi + Bluetooth solution for wireless connectivity. The implementation in the ZenPad S supports two spatial streams on 802.11ac, which allows for a peak theoretical link speed of 867Mbps. However, the ZenPad S has a software problem that makes real world speeds significantly lower than that.
You may be wondering why the ZenPad S can only get a maximum speed of 173Mbps over UDP when the ZenFone 2 with its 1x1 802.11ac goes as fast as 293Mbps. You may have also noticed that a speed around 150Mbps is very similar to devices with 2x2 802.11n WiFi, and that's exactly the problem. The ZenPad S only works in 802.11n mode, a software problem that should have been found in testing long before the tablet actually shipped. I have tested the ZenPad S with an Apple Airport Extreme 6th gen and a TP-Link Archer C7, and the max link speed remains at 200Mbps in both cases. ASUS has confirmed the issue on their end and is aware of it, and so a software fix should arrive for it at some point. Users are, at the moment, just going to have to live with WiFi that isn't even half as fast as it would be if it was working properly.
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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?