Asus ZenFone 2 Review

Conclusion

Designing a phone for the middle of the market is tough. A flagship device gets all the bells and whistles, while a low-end device gets the bare minimum to hit its target price. In the middle, however, the OEM needs to find just the right balance between design, features, performance, and price. Fall short in just one area and the phone is a flop. For the ZenFone 2, Asus finds this balance. Performing better and costing less than its peers offsets the few minor issues we found with ergonomics and the display.

Despite its low cost and all-plastic construction, the ZenFone 2 does not feel or look cheap. The faux brushed metallic finish looks convincing and the body feels rigid and sturdy. The only rough edge, literally, is around the perimeter of the front face, which feels scratchy when held against the ear.

We do have some minor quibbles about ergonomics. Asus places the volume controls on the back and the power button on the top edge. While this gives it a streamlined look and reduces inadvertent button presses, the power button is very difficult to reach considering how tall the phone is. This issue is mostly mitigated, however, by the ability to wake or sleep the device by double tapping the screen, a feature we love and wish every phone had. The rear-mounted volume rocker is placed within easy reach, although we wish it were a bit wider and had some sort of detent in the middle to make it easier to locate. Another minor issue is that the capacitive buttons are only coated with a reflective material and are not backlit, causing us to fumble for the correct button in the dark on more than one occasion.

The ZenFone 2’s sharp looking 5.5-inch IPS LCD display sports a 1080p resolution and 401 PPI pixel density, a definite plus considering many large-screened phones in this price range only have a 720p resolution. Asus also provides a few different display modes and some manual controls for adjusting the screen’s appearance. While the factory modes are not stellar in terms of grayscale or color accuracy, a simple adjustment of the color slider improves the display accuracy significantly.

While the ZenFone 2’s display is good, there are two things holding it back from being great. The first is maximum brightness. By default, Asus caps brightness to just over 300 nits, which makes outdoor viewing more difficult. Using a third-party app to control display brightness unlocks the backlight’s full potential, boosting the display to ~400 nits, an acceptable value. The second, more serious, issue is the display’s gamma curve. Linearly increasing with luminance, the high gamma gives the screen a dark cast, washing away shadow detail and hurting color accuracy.

The 13 MP camera lacks advanced features like OIS and PDAF, which is common for phones in this price range, but it is accompanied by a dual-color LED flash. The ZenFone 2 also lacks support for Lollipop’s Camera2 API. Despite this, Asus’ streamlined camera app does have a decent manual mode and offers smart suggestions for which of the several different shooting modes to use, including a good HDR mode that not only controls dynamic range well, but also avoids the most common post-processing artifacts.

Image quality in good lighting is decent, but it tends to set the white balance a bit too cool. It also tends to overexpose images when not using HDR mode. The Toshiba rear camera sensor seems to struggle with low-light sensitivity, leading to darker images with visible noise. Asus does not appear to use any noise reduction algorithms, which makes the noise more visible, but also avoids the artifacts and loss of details that result from its overuse. The rear camera also has trouble capturing color info in lower-light conditions, making images appear a bit muted and undersaturated.

Like most mid-range phones, shooting video with the ZenFone 2 is a no-frills affair. Video quality at 1080p is ok, but the lack of continuous autofocus and an HDR video mode hurts the experience. You also do not get access to any advanced video modes, including 4K, 60fps, or slow motion.

One thing about the ZenFone 2 that did surprise us is its excellent audio quality. While it does not have front-facing or even stereo speakers, its lone rear-facing speaker actually sounds pretty good. The ZenFone 2’s headphone audio quality even rivals some of the best flagships we’ve heard.

Asus’ ZenUI was another nice surprise. Sure, Asus includes quite a few of its own apps, not all of which are useful, but it’s easy enough to sweep them out of the way. Where ZenUI shines is in its flexibility. It includes a good theme engine and the launcher includes a depth of customization usually reserved for third-party ROMs. Asus’ ZenMotion suite includes useful features like the ability to launch apps by drawing letters on the screen and a nice one-handed mode too.

At the beginning of this (novel length) review, we questioned whether the ZenFone 2’s Atom SoC could compete with its ARM-based competition in terms of performance and power given Intel’s past struggles in mobile. In terms of peak theoretical performance, Intel still has a ways to go to match the best offerings from ARM and Apple. However, when it comes to more realistic workloads, Atom does fairly well. Along with decent NAND read speeds and a memory controller that performs well with random memory accesses, the Atom-powered ZenFone 2 performs as well as, or in some cases better than, more expensive flagship phones. Pairing the Atom Z3580 SoC with a 3000mAh battery gives the ZenFone 2 pretty good battery life as well. It appears that Atom can compete in the power consumption arena too.

The ZenFone 2 turns out to be a surprisingly well-rounded device considering it only costs around $300 or less unlocked. Most OEMs offering phones in this price range make serious concessions that compromise the user experience to reduce cost. Asus avoids this pitfall, creating a phone that meets (camera) or exceeds (performance and features) our expectations for a mid-range device. This is why the Asus ZenFone 2 is Editor Recommended.


MORE: All Smartphone Content
MORE: All Tablet Content

Brian Magsipoc is an Associate Contributing Writer for Tom's Hardware, covering Smartphones.

Matt Humrick is a Staff Editor at Tom's Hardware, covering Smartphones and Tablets. Follow him on Twitter.

Follow Tom's Hardware on Twitter, Facebook and Google+.

This thread is closed for comments
30 comments
    Your comment
  • wtfxxxgp
    I like the look. I love the price. Seems like a gem of a phone if good value is more important to you than the latest and greatest tech. I wonder if it'll be available here in South Africa...
  • manitoublack
    Great to read this review of someone doing something different.
  • MasterMace
    2 things that ding the phone before it even started: locked battery, 1080p screen. The LG G4 and Galaxy S6 both have 1440p screens. The LG G4 has a removable battery.
  • edwd2
    Quote:
    2 things that ding the phone before it even started: locked battery, 1080p screen. The LG G4 and Galaxy S6 both have 1440p screens. The LG G4 has a removable battery.


    Yeah, but the G4 and S6 also cost a whole lot more. Not to mention that the G4's A418 has trouble powering that 1440p res while the G6430 is just fine with a 1080p screen.

    And what does LG have to offer in the $200 price range? The LG G-Stylo runs a crappy SD410 and 720p display.
  • g-unit1111
    I wish we'd embrace the concept of dual SIMs and unlocked phones more here in the States. This is a very nice phone for the price and more carriers should be able to use it, right now it seems like only AT&T and Verizon can use it, leaving T-Mobile and Sprint out of it.
  • PC98226
    Great review. I was looking for your comments re: this device's ability to maintain wireless connectivity. I have been using the 4GB version of this phone for several months now. While I found it to have a VERY snappy speed, I experienced some quirks re: it connectivity. I would frequently have to check why the phone stalled trying to open up a web site only to realize that it had switched the connection from my WiFi to my wireless printer. This happened so frequently that it slowed me down re: productivity. I suspected there was some type of software glitch that needed to some attention. So, until that happens, I have returned to using my Moto X (2014). During your testing of this device, did you see or experience anything like the above?
  • MRCPU
    I own one of these, and I really like it. Asus has been very good about pushing fairly regular software updates, much faster than any carrier. For a time, it seemed like updates were hitting like clockwork about every 2 weeks.

    However, the one downside to this phone is the *massive* amount of bloat. The author touches on it a bit, but did not convey how much pure crap resides on this phone stock.

    However, there are many fixes available to that problem. A quick google for debloating scripts will get you headed in the right direction.

    My only other gripe is that mp3-based notification tones don't seem to consistently stop if you like touch the screen, or acknowledge the notification, you can't flip the phone over to silence it like on the Galaxy series. But these are minor nits.

    I get a full day of usage out of my battery, the quickcharge is nice, and for 300 bucks, the extra features of the other phones aren't appealing enough.

    I recommend this phone to anybody.
  • PC98226
    "....However, the one downside to this phone is the *massive* amount of bloat. The author touches on it a bit, but did not convey how much pure crap resides on this phone stock."

    Yes, I totally agree re: the massive amount of crapware pre-installed on this device. I tried to either uninstall or disable all that I could (nearly 33 apps in all) before I installed the apps I wanted to use. Now, these apps no longer auto-update so that is a help.
  • GoZFast
    I owned this phone from newegg since late May and I have to say that its the best phone I have ever had over LG, Samsung, iPhone, Blackberry etc The kernel is 64 bit but not the OS. Asus are working on a completely x86_64 Intel OS based on Android/Linux source code. Some apps are not x86 compatible yet but when they are, they run much more efficient than ARM. Its price of 299$ for the top 4Gb RAM model is too good for what it offers and if you even want more, you can join ZenTalk beta forum. With beta firmware, the phone is faster and battery lasts longer, never had an issue with beta firmware so far. This is also the coldest phone I have had, much colder than G3 and G2. Anything over 1080p in a 5'' device is pointless and will just consume more battery, create more heat and put a high load on the GPU. What also amazed me is that you can run 128Gb SDcards EVEN if the specs says 64Gb (Lexar 633x) The 18W 9V2A charger is faster than Samsung's 9V1.67A adaptive charger. Here is my newegg review, basically, the Atom CPU beats the SD810 and S6 in single threaded performance (Floating-point and Integer), it only loses in multithread (Hence, higher Antutu score) because its rivaling 8 cores so imaging doubling this in a future phone! I also doubt that playstore apps will take advantage of 8 cores like Anututu and hence, their higher score doesn't mean that 4 core or less apps will be faster. Intel can easily add more cores with 14nm but other are already 8 cores with 14nm and it will be very hard to increase performance with more than 8 cores. Intel Core M with Intel GPU in tablets is 3.5W while the Atom is 2.2W. If Intel can find a way to integrate it into smartphone, it will be a heck of a phone considering that it gets ~3000pts in PassMark similar to Intel Core i5-3317U or an AMD A10-5757M.

    Pros: Intel 64bit 3D 22nm Quad 2.33Ghz
    4GB Ram, did I underscore its speed?
    This outperforms all current cellphones (yes, faster than snapdragon 810) and have lots of headroom for improvement on intel architecture with more instruction sets for programming. We will probably see this device quad boot; android:windows:linux:mac os x
    Lots of potential.
    9v 18w charger! Higher than 12w ipad lol

    Cons: PowerVR G6430, same architecture as iphone 6+ but this intel extracts more gpu power vs dual-core 1.4ghz apple.
    Wish it had intel graphics which is up to 4x more powerfull than Adreno 430, highest current mobile gpu. Intel graphics would also throw more compatibility and instruction sets into the table.
    14nm and 3200mah maybe?
    Camera could be better (4k?) but not a fan of photography, it does what it says.

    Other Thoughts: For more battery life, put screen into reading mode and dim it as the default setting is very bright. Also, there is option to powersave in settings. You can also remove unnecessary apps, use system app remover for system apps (Not needed with Beta firmware) Getting better battery than my old g3.

    p.s: With beta firmware, you can disable/uninstall any app you want, even system apps without root. Root will break OTA and live beta updates. Many of these apps are actually useful though. Also, I found that Nova launcher decreased RAM usage by 80Mb and its snappier (Doesn't need root)
  • fyend
    Asus rivals Samsung with the amount of uninstallable crapware they preload on their phones. If you're planning to root, that's fine you can remove it all, but if not you're stuck with a lot of junk.
  • GoZFast
    They might push their beta firmware to all users and make everything uninstallable. Otherwise, you can currently do that with their beta fw.
  • Niva
    Quote:
    2 things that ding the phone before it even started: locked battery, 1080p screen. The LG G4 and Galaxy S6 both have 1440p screens. The LG G4 has a removable battery.


    The 1080 screen is a bonus, allows for better performance than the useless 1440 screens on the devices you listed. Your GS6 example also doesn't have a removable battery, and the G4 has that terrible pairing of a QHD screen with a SD 808. Both of those phones are much more expensive than this one.
  • William_2
    Dam nice device thanks replaced my motto x with the 4gig ram unit no headaches yet and the bloat can be uninstalled or stopped easily nicest device at this price point ..
  • jabarumba
    I want the PC take on things. I can't wait to get a device, put on a clean copy of Windows 10 without the smartphone bloatware and other garbage (except the Win garbage that I get anyway from my PC) and simply have a PC that occasionally makes phone calls and fits in my pocket.
  • Memnarchon
    Guyz, I am not sure that I am searching for the right phone, but both in gsmarena and the official site have the asus zenfone 2 base (ZE550ML) as a phone with 720p IPS screen and not 1080p... :(
  • bmagsipoc
    Quote:
    I experienced some quirks re: it connectivity. I would frequently have to check why the phone stalled trying to open up a web site only to realize that it had switched the connection from my WiFi to my wireless printer. This happened so frequently that it slowed me down re: productivity. I suspected there was some type of software glitch that needed to some attention. So, until that happens, I have returned to using my Moto X (2014). During your testing of this device, did you see or experience anything like the above?


    I personally didn't notice anything like that during testing. But I don't have a WiFi printer either. The Zenfone 2 seemed to hang on to WiFi signal about as well as most of my other devices, maybe a little below average but normal for the most part.
  • MobileEditor
    Quote:
    Great review. I was looking for your comments re: this device's ability to maintain wireless connectivity.... I experienced some quirks re: it connectivity.


    I also did not notice any issues with Wi-Fi on the ZenFone 2 using a 2.4GHz channel. I did not try the ZF2 on a 5GHz channel, but I've noticed that several Android devices do not play well with my particular wireless router on 5GHz (even though other phones/tablets/laptops work ok) but work fine on 2.4GHz. The LG G4, for instance, randomly drops the Wi-Fi connection, and the new Galaxy S6 edge+ cannot even see the network, even though both devices are within two feet of the router. You may try switching your router to one of the lower 5GHz channels to see if that helps.

    - Matt Humrick, Mobile Editor, Tom's Hardware
  • Onus
    It started to look good, but I stopped reading at "non-removable battery," because that is a dealbreaker. It guarantees the device will need repair or that it will eventually become a brick, even if it has otherwise been meeting the needs for which it was bought.
  • captaincharisma
    Quote:
    It started to look good, but I stopped reading at "non-removable battery," because that is a dealbreaker. It guarantees the device will need repair or that it will eventually become a brick, even if it has otherwise been meeting the needs for which it was bought.


    face it, all high end smartphones are going to have non-removable batteries soon. and considering this asus is low end and it has a non removable so if you are looking for a high end, premium smartphone in the future expect it not to have a removable battery or even an SD card slot.
  • efok
    1814010 said:
    Quote:
    Great review. I was looking for your comments re: this device's ability to maintain wireless connectivity.... I experienced some quirks re: it connectivity.
    I also did not notice any issues with Wi-Fi on the ZenFone 2 using a 2.4GHz channel. I did not try the ZF2 on a 5GHz channel, but I've noticed that several Android devices do not play well with my particular wireless router on 5GHz (even though other phones/tablets/laptops work ok) but work fine on 2.4GHz. The LG G4, for instance, randomly drops the Wi-Fi connection, and the new Galaxy S6 edge+ cannot even see the network, even though both devices are within two feet of the router. You may try switching your router to one of the lower 5GHz channels to see if that helps. - Matt Humrick, Mobile Editor, Tom's Hardware


    I have been using the 4GB version of this phone since June and it works perfectly on 5Ghz wifi without issues. Usually on the Hitron cable modem at home.
  • Glock24
    This is one of the few unbiased and id-depth reviews of this phone, congratulations! I wonder what software version did your test units run. Asus has been consistently pushing updates that have improved the experience, adding some features here and there, reducing the battery drain, improving camera performance, etc. The early reviews reported bad camera performance and high battery drain, and thus gave it a poor score.
    I´ve owned this phone for about two months now, and I cannot be more happy with it. Performance wise it´s great, comparable or better than many flagships, and definitely better than anything in it´s price range. Battery performance is average, but after reading lots of reviews of the current batch of flagships and midrange offerings, I cannot complain, as it fares really well, and has improved with software updates.
    Most people complain about the button placement, but I´m one of the few that really like the power button on top, as it prevents accidentally pressing it. If you find it difficult t press it, just double tap to wake or sleep! Volume buttons took a couple of days to get used to, but also like it now.
    As for the bloatware, I think it´s been exaggerated by most people. Yes it comes preloaded with some useless programs, but some can be uninstalled and others can be disabled. Some are really useful additions, like kids mode (better than some 3rd party programs I´ve used), app locking, startup manager, etc.
    The Zen UI is the best non-stock Android UI I´ve used, I really like it. It´s pretty light and does not get in the way, unlike Samsung´s. As you can see in this article, even though the ZenFone2 has more RAM, it also has less bloat than Samsung S6 and Note 4:
    http://www.techarp.com/showarticle.aspx?artno=897&pgno=0
  • MobileEditor
    Quote:
    This is one of the few unbiased and id-depth reviews of this phone, congratulations! I wonder what software version did your test units run.


    The performance assessment and photos were taken with software version 2.19.40.22_20150627_5104.

    - Matt Humrick, Mobile Editor, Tom's Hardware
  • Textfield
    It's disappointing to see how low the per-clock performance is on the Atom.
  • KaiserPhantasma
    sounds like a phone that'll fit like a glove to me =D