ASUS ZenFone 5 review: Budget X

Note: This article was first published on 23rd May 2018.

Back on track

The ASUS ZenFone 4 may have only been released a mere six months ago, but ASUS is already back with a new ZenFone, and, at S$488, it's thankfully much cheaper than its predecessor.

The ZenFone 5 returns the ZenFone brand to its roots, and offers a premium design and mid-range performance all in a very affordable package. Oh, and it also looks almost exactly like an iPhone X.

N.B. Due to some unquestionably poor planning on the part of ASUS, this is also the ZenFone 5: 

This ZenFone 5 came out in 2014 as part of the first wave of ZenFones - the 5 referred to the size of the display. If you're buying a ZenFone 5 on Carousell or HardwareZone's Marketplace or some other non-authorized source, make sure you're getting the 2018 version.

What do I get in the box?

To answer that, here's our quick unboxing video!

Play

Haven't I seen you before somewhere?

Notches are the hottest design trend of 2018 with everyone from Oppo to LG getting in on the action. It's a trend that probably won't be going away anytime soon either, with Google recently announcing notch support for Android P.

ASUS was one of the first brands to jump on the bandwagon, when it revealed the ZenFone 5 at MWC 2018 earlier this year. But the ZenFone 5 borrows more from the iPhone X than just its notch, it also has rounded display corners, and a vertically-orientated dual camera setup, and the end result is a phone that could easily be mistaken for Apple's flagship.

However, there are a few giveaways that will help you spot a ZenFone 5 in the wild. The phone's aluminum frame has chamfered bevels (another trend originally started by Apple - although it's long since abandoned them), and there's a circular fingerprint scanner on the back of the device. The rear of the phone also sports ASUS's signature concentric circle design.

Like the iPhone X, the dual rear camera setup sits in the top left corner. On the ZenFone 5, you get a 12-megapixel f/1.8 24mm lens paired with an 8-megapixel f/2.0 wide-angle lens. There's a small camera bump, but it isn't too bad.

Size-wise, the ZenFone 5 with its 6.2-inch screen is slightly larger than the iPhone X, and is actually about the same size as ASUS's previous 5.5-inch ZenFones. It measures 153 x 75.7 x 7.9mm and weighs just 155g, which is quite light for a phone this size. For comparison, the smaller iPhone X weighs 174g.

The right side of the phone houses both the power button and the volume rocker, while the nano-SIM card tray and microSD card slot can be found on the left side. 

On the bottom, you'll find a downward firing speaker grille, a USB Type-C port and another dead giveaway that this isn't an iPhone X: a 3.5mm headphone jack. There's also a small microphone down here.

The ZenFone 5 is available in two colors. My review unit is Midnight Blue. There's also Meteor Silver, which looks like this:

Overall, despite its obvious "inspiration", the ZenFone 5 still looks great, and both looks and feels a lot more premium than its S$488 price tag would suggest. It's definitely the nicest looking phone ASUS has ever made. The only thing that would make it better is some form of dust and water resistance.

Display & Audio

The ZenFone 5 has a 6.2-inch IPD LCD display with an 18.7:9 aspect ratio and a 2,246 x 1,080 pixels resolution (~402ppi). The display is bright with reasonably good contrast for an LCD screen, although it obviously pales in comparison to an OLED display. The display has support for the wide-gamut DCI-P3 color space and is fairly neutral and color accurate by default. However, it does not support HDR videos like many flagship phones.

As Android 8.0 does not offer notch support (something that will change in Android 9.0), quite a few apps will display with content hidden behind the notch. At launch, there was no way to disable the notch, but the most recent ZenUI update has added an option to do so.

The phone has an "AI Display" feature, which automatically adjusts the brightness, temperature, and color of the screen depending on your lighting as well as the content that you are currently viewing or watching. There really isn't any "AI" at work here (it just uses the ambient light sensor) and the feature is basically the same as Apple's TrueTone display, generally making the display a little warmer, and easier on the eyes.

Audio on the ZenFone 5 comes from a single downward-firing speaker. Despite the modest setup, audio on the phone is surprisingly loud and clear. It doesn't have much in the way of bass or high-end, but it's good enough for when you can't be bothered to plug in your headphones.

Nearly stock Android

The ZenFone 5 runs on Android 8.0 with ASUS' ZenUI on top of it. ASUS has cut back on its own apps, and you'll no longer find duplicate versions of the browser, email, keyboard, or messaging apps that ASUS used to pre-install. There's no button for the app drawer, but you can access it by swiping up from the home screen.

As with most ASUS phones, there are quite a lot of pre-installed software features. There's a Face Unlock option, which, just like the iPhone X, can be used with a raise to wake gesture. ASUS's version of Face Unlock simply takes a picture of you during setup and compares it when you're unlocking your phone. It unlocks quite fast, but only really works in well-lit environments. I wasn't able to fool Face Unlock with a picture of me, but it's still not secure enough to use with any biometric payments, so it's really just for convenience.

There's also an AI ringtone option, which is really pushing the limits of what you can call AI, as it just automatically adjusts the loudness of the ringtone depending on whether you’re in a quiet or loud environment.

There's also a Twin Apps option, which we've seen on a number of other Android phones, which lets you create a second version of an app so you can manage two accounts at the same time. There's also something called OptiFlex, which apparently speeds up the startup of selected apps, although I didn't really notice it doing anything.

Finally, there's ZeniMoji, which as you can probably guess, is ASUS' version of Apple's Animoji, allowing you to use your own facial expressions to animate cute avatars.

ASUS uses a combination of 52 different expressions to mimic yours, and it can also be used in video calls or live streams on social media. Here's a video from ASUS to get more acquainted:-

Play

Obviously, the phone doesn't have the iPhone X's 3D depth-sensing camera, so instead it uses an algorithm trained on hundreds of thousands of 2D faces with different expressions, lighting conditions, and angles. The algorithm then makes use of this data to approximate a 3D model of your face.

It sort of works, but is quite limited in application. If you smile, your ZeniMoji will smile, but it's nowhere near the 1-to-1 capture you get with Animoji.

Benchmark Performance

The ZenFone 5 is powered by a mid-range Qualcomm Snapdragon 636 processor with 4GB RAM. This is actually a downgrade from last year's ZenFone 4, which used a 660 processor, but it's also why the ZenFone 5 is a lot more affordable.

There aren't that many phones using Qualcomm's 636 processor - the most notable being Xiaomi's Redmi Note 5 Pro, which unfortunately we don't have on hand - so we'll be comparing the ZenFone 5 to other mid-range processors including the 625-powered Redmi 5 Plus, and 660-powered Oppo R11s. We've also included the Snapdragon 835-powered Xiaomi Mi MIX 2, which is now available for S$590, just S$102 more than the ZenFone 5.

N.B. The ZenFone 5 has a feature called AI Boost. The phone will ask you if you want to turn it on anytime you start a game or benchmark, as well as a few other compute-intensive apps. You can toggle it on/off yourself from the Quick Settings menu by tapping the rocket ship icon. When turned on, you'll be warned that "AI Boost may slightly affect battery usage time."

For the following benchmarks, the light green bar is with AI Boost off, while the dark green bar is with AI Boost on.

SunSpider Javascript

SunSpider JavaScript measures the browsing performance of a device when processing JavaScript. It not only takes into consideration the underlying hardware performance, but also assesses how optimized a particular platform is in delivering a high-speed web browsing experience. 

The ZenFone 5's 636 processor fared about as well as expected, scoring in between the 660-powered ZenFone 4 and the 625-powered Xiaomi Redmi 5 Plus. Surprisingly, AI Boost actually lowered the ZenFone 5's score here quite a bit. This test is run in Chrome, so I didn't expect it to make much of a difference, but it was over 100ms faster.

Basemark OS II

Basemark OS II is an all-in-one benchmarking tool that measures overall performance through a comprehensive suite of tests including system, internal and external memory, graphics, web browsing, and CPU consumption.

The ZenFone 5 performed a bit better here, and was closer to the higher performing 660-powered devices than the 625-powered Redmi 5 Plus. AI Boost also closed the gap a little further.

3DMark Sling Shot

3DMark Sling Shot is an advanced 3D graphics benchmark that tests the full range of OpenGL ES 3.1 and ES 3.0 API features including multiple render targets, instanced rendering, uniform buffers and transform feedback. The test also includes impressive volumetric lighting and post-processing effects. We're running this benchmark in Unlimited mode, which ignores screen resolutions.

In this benchmark, the ZenFone 5 was once again in between the ZenFone 4 and the Redmi 5 Plus. Unfortunately, AI Boost didn't do much for this benchmark, which suggests it's mainly for processor-intensive apps, and won't help much with graphics.

Imaging

Like last year's ZenFone 4, the ZenFone 5 has a dual-camera setup at the rear pairing a 12-megapixel f/1.8 main lens with 4-axis OIS (optical image stabilization), with an 8-megapixel f/2.0 wide-angle lens. In addition, the ZenFone 5 also sports a newer Sony IMX363 image sensor.

Image quality from the main lens is quite good, especially for a mid-range phone, with good color reproduction, a high level of detail and contrast and fairly low noise. Auto-focus is fast and accurate, and only struggles in really poor lighting conditions. Shots tend to be slightly overexposed, and there is some slight lens distortion if you look closely, but it's not too bad overall.

Photos from the wide-angle lens show noticeable fisheye lens distortion, although color reproduction and contrast is still quite good. In general, you're better off using the main lens, but if you really need to take a big group photo and you can't back up any further, the wide-angle lens will do in a pinch.

AI-assisted photography

The camera now also boasts a number of AI features to help you take better photos.

We've already seen AI-assisted photography in Huawei and LG's phones, and ASUS's approach is fairly similar. The main AI feature is AI Scene Detection, which identifies the scene or subject a user is shooting and automatically applies the ideal settings for the best results. This takes into account things like color saturation, white balance, exposure and brightness, auto exposure time, sharpness, and noise. 

It is capable of detecting 16 different scenes:

• People
• Food
• Dog
• Cat
• Sunset 
• Sky
• Green field
• Ocean
• Flower
• Plant
• Snow
• Night view
• Stage
• Text
• QR code
• Tripod 

You'll notice the camera can distinguish between cats and dogs, and ASUS says that's because it wanted to take into account different expectations when shooting the two. For example, dog owners tend to have the luxury of having more time to frame the shot of their pup, whereas cat owners may want to capture their feline in action. In the latter case, the ZenFone 5 will apply a faster shutter speed.

The camera is generally quite good at identifying objects, but it can sometimes be fooled if there isn't enough context or two items look too similar.

The ZenFone 5 camera also uses AI to learn the type of photos that owners want through something called AI Photo Learning. The phone presents you with identical photos treated with slightly different image settings and lets you pick the one you like best. Over time, the camera comes to understand your preferences, and it then applies what it thinks is the best setting to replicate a similar look and feel for future shots.

The settings derived from AI Photo Learning also take precedence over those that the AI Scene Detection feature may suggest. However, not all scenes and subjects are supported, and compatible photos will be marked by an icon in your photo library. Unfortunately, I haven't really had enough time to notice AI Photo Learning do anything yet.

Other "AI" features include AI Beautification and AI Portrait, which works best for those who like to take selfies. The beautification mode is smart enough to detect the gender of subjects and apply digital makeup for women.

ASUS says it's analyzed over 100 different shades of skin color for the best results, and captures facial details using a scanning pattern with 365 dots. The effects can also be applied in video while live streaming on popular social media platforms.

Finally, AI portrait mode applies a bokeh effect to the background in real-time, and it works with both the front and rear cameras on the ZenFone 5.

Battery Life

Our standard battery test for mobile phones has the following parameters:

• Looping a 720p video with screen brightness and volume at 100%
• Wi-Fi and Bluetooth connectivity turned on
• Constant data streaming through email and Twitter

The ZenFone 5 has a 3,300mAh battery, which is about the average capacity for a phone of this size. The phone ran for 8 hours and 19 minutes, which was slightly better than the ZenFone 4 and Redmi 5 Plus, but fell far short of the Oppo R11s with its power-efficient AMOLED display. Running this benchmark with AI Boost turned on also resulted in a significant decrease in battery life, with over an hour lost. My advice is to only turn on AI Boost for CPU-intensive tasks, and only if the app is struggling without AI Boost.

The ZenFone 5 uses ASUS' own Boostmaster technology for fast charging, which charges the phone relatively quickly - you'll get about 50 percent charge in 30 minutes. The phone also includes an AI charging feature, which claims to "dynamically adjust the charging rate based on your previous charging behavior" This is supposed to extend the lifespan of your battery by varying the charging pattern to suit your usage habits. For instance, if the phone learns that you tend to go to bed at 10pm, it'll charge slower to reduce heat and avoid overcharging. Despite having a glass rear, the phone does not support wireless charging.

Conclusion

If you can get over the ZenFone 5's not particularly original design and features, it's actually a really nice phone that punches well above its weight. It looks and feels premium and offers a lot for its modest S$488 price tag.

Having said that, ASUS is really stretching the limits of what can be considered "AI", and I really don't appreciate it misleading consumers with its multitude of "AI" features that are clearly not, such as AI Display, AI Boost and AI Ringtone. It's not that these features aren't smart or useful, but they don't involve any machine learning, which is generally considered a requisite for AI. The only feature I consider where AI is actually being used on the ZenFone 5 is the AI image recognition in the camera.

ASUS has smartly priced the ZenFone 5 right below the usual crowd of budget flagships from the likes of Xiaomi and OnePlus, and as such, it doesn't have a lot of competition in its sub-S$500 price category. Other than a weaker processor, it actually compares quite favorably to more expensive phones like the Mi MIX 2 and OnePlus 5T. Its Snapdragon 636 isn't the fastest out there, but it handles most tasks fairly well, and if you mainly use your phone for web browsing, sending messages and watching videos, it's more than enough. If you really can't live without a top of the line processor, you can always wait for the Snapdragon 845-powered ZenFone 5Z, which will be available later this year, and should also be quite competitively priced.

Overall, the ZenFone 5 offers plenty of flagship features at a very reasonable price. After a misstep with last year's ZenFone 4, I'm happy to see a return to form for the ZenFone brand. If you're looking for great value without feeling like you're settling for a budget device, look no further.

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