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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MrSavage - Monday, August 31, 2015 - link
Aside from possibly mentioning the stylus support in the review. I would imagine with that logic, you would assume the S Pen is no biggie when it comes to the Samsung Note. Like just a passing point. It's not like the note taking is a selling point (a big one at that) of the Note series. But in this tablet review, your readers wouldn't even know it existed. I guess you decide on what's the responsible way of reporting on a product.Kepe - Monday, August 31, 2015 - link
The difference is that a Galaxy Note always comes with the pen. How could you review something you don't have? If ASUS had sent him the stylus, he would've written about it. You can't possibly assume that a review mentions every optional extra there is available for a device. "Oooh, your laptop review sucks because you didn't mention the carrying bag or the Kensington lock available for that laptop!!"MrSavage - Monday, August 31, 2015 - link
Friend, again, the point is what? A stylus is a BIG VALUE ADD. No? I give you the example of the Samsung Note to prove that it's a big selling point. To have that feature in the Z580CA yet not have it mentioned it actually irresponsible. You speak of it like it's some smart case that wasn't available at the time of publishing. Optional extra? LOL. List 8-inch tablet with stylus support. Then narrow that list down to similarly priced tablets. None? Right. Leave it out of the review because stylus is just so meh. You are dazzled by charts and graphs that compare apple with oranges and are willing to see a graph to make a determination on screen quality rather than going into a store and looking for yourself.Kepe - Monday, August 31, 2015 - link
omg. Now you're saying a stylus doesn't add value to the product. Then why are you crying about stylus support not being mentioned in the review?And the thing with screen quality is that it is all about accurate color reproduction. So if there is a faintly red flower in a photo, it should look faintly red on your display. If it looks like a hot super bright red flower on a display, then that display is not accurate and isn't good. Even if it makes some things "look" better. Samsung Galaxy S3 for example. Pictures look super pretty on its display. You know why? The display oversaturates everything, and as such it is actually not accurate and not a good display. If you personally like to look at oversaturated things, then buy the SGS3, no one is stopping you. BUT the fact still remains that the display isn't accurate. This was of course just an example. Some things can't be quantified by just looking at it or feeling it somehow.
And this is my last reply to you. Hope ASUS pays you well. Have a good night with your mediocre, badly made tablet. Thanks to the review, I will look elsewhere if and when I need a new tablet.
superflex - Monday, August 31, 2015 - link
Is ASUS paying you in Hot Pockets?You're a pretty poor troll.
MrSavage - Monday, August 31, 2015 - link
@superflex if you care to debate any of the points I'm making, go ahead. I likely know more about the product than most, so I'm going to inform people and hope that people with a large audience will be responsible. If for nothing more than being professional. Like I said, you think I'm wrong about anything I've said in the comments, please advise me. I have a thick skin. People might have learned that the Z580CA has stylus support, so to say that makes me a troll? I only take issue with unprofessional.Winterblade - Monday, August 31, 2015 - link
Is just sad that everyone just forgot another great alternative, the Xperia Tablet Compact, too sad it came dead on arrival due it's high price, I actually found one in clearance for about $230 USD and could not be happier, the build quality is superb, the performance is too, it was even updated to 5.1.1 within the first few hours I had it. If only Sony had managed to sell it for around 300-350 I think it would have been a very very good alternative for people that like mid sized tablets. BTW, the Z3 have an aluminum frame AND is lighter AND thinner than the Zenpad so... it is posible to achieve a lighter device without going full plastic.DanNeely - Monday, August 31, 2015 - link
Sony has a negligible presence in the US market; and their longstanding refusal to provide review samples more or less guarantees their largely being ignored by the US tech press.They make above average hardware; but it doesn't matter to me. I'll be carrying my grudge against them over the rootkit to the grave.
et20 - Monday, August 31, 2015 - link
Thank you for the review.This tablet looked interesting and there's nothing like an Anandtech review to clarify things.
I was interested in the cheaper model so I had proportionately low expectations, but the poor screen calibration is a deal breaker. Too bad.
MonkeyPaw - Monday, August 31, 2015 - link
As a bit of feedback, I think better pictures of the products are needed in these reviews. As I look at these photos, I just can't help but think of someone awkwardly holding a tablet out with one hand while trying to photograph it with the other. I know not everyone is a photographer, but good, clean, properly lit product shots go a long way for a professional look. Make a little product photo booth out of white paperboard/foamcore and mount a camera on a tripod for flashless photography.