- Nice design
- Feature packed
- Flexible camera tech
- Long battery life
- Unintuitive software
- Android Nougat + ZenUI 4
- 12MP + 8MP wide angle
- Snapdragon 630
- 64GB + microSD
- Fingerprint sensor
The Zenfone 4 is one of Asus’ first smartphones to make it to the UK in some time, besides the super-expensive Zenfone AR that is. Boasting a feature-packed dual-lens camera and the nifty ZenUI OS, the Zenfone 4 is an enticing mid-range mobile and possible alternative to the OnePlus 5.
At £450/$585, Asus’ new Zenfone 4 is placing itself as a direct rival to the latest OnePlus handset. They share the same UK asking price, as well as many similar features; both of these mobiles offer a dual-lens camera and a Full HD 5.5-inch display, for instance.
It’s a brave move to go up against the OnePlus 5, which sports some very strong specs for a very reasonable cost. Of course, the Honor 9already managed to impress us just as much in pretty much every respect, even undercutting OnePlus with a £380/$494 price tag. Great stuff, considering the excellent camera tech, powerful processor and solid specs.
So, how does the Zenfone 4 fare, in a market where few people have even heard of an Asus smartphone let alone touched one? Here’s my full review after using the Zenfone as my full-time phone for a week.
Asus has had a fair bit of practice by now when it comes to smartphone design, so the Zenfone 4 certainly doesn’t disappoint. While the aesthetics aren’t particularly stand-out, this device sports a smart and attractive finish that suits the mid-tier asking price.
That aluminium unibody frame is coated in glass around back, for a shiny appearance that mimics the front. That glossy rear does a pretty good job of masking fingerprints and other marks; at least, in the midnight black model, which we tested. You can also grab the Zenfone 4 in white here in the UK.
Of course, one drawback of that smooth surfacing is the slippery grip. Place the handset on a slightly inclined surface and it will inevitably begin a steady slide, while clutching the phone requires a sturdy grip (and preferably non-sweaty palms). Thankfully the Zenfone 4 so far seems more sturdy than the Honor 9. No cracks or scratches have appeared on our review model, although we have seen scratches on some other reviewers’ handsets.
One design feature that we do enjoy is the circular patterns that shine across the rear surface when the Zenfone 4 catches the light. This is a funky effect that Asus has used countless times before on its devices and it works well here.
You don’t get a water resistant finish, although the handset seems to cope just fine with rain and splashes.
The Zenfone 4 appears to be hardy enough to survive everyday life, including the odd bit of rough treatment such as being tossed into a bag. That design is rather attractive too, if not particularly stand-out, with camera lenses that lie flush to the surface.
The glass surfacing makes for a slippery grip, while there’s no water resistance to speak of.
Screen & Media
Media fans have plenty of reason to invest in the Zenfone 4.
For one, the 5.5-inch IPS screen is as strong as any of the competition, certainly at this price point. You get Full HD visuals, so your photos and videos will look sharp despite the large panel size, while the brightness levels are strong enough for easy viewing in bright daylight.
Colours are pleasing to the eye, without proving unnaturally vibrant, although you can fiddle around with hues and saturation levels in the Zenfone’s display settings if you fancy it. There’s even a ‘vivid’ setting, if you want your visuals to really pop from the screen. On top of that you have a blue light filter feature, which produces warm, easy-on-the-eye visuals for more comfortable night viewing. Sadly there’s no kind of timer to automatically activate this in the evenings, which means you’ll need to manually turn it on every night instead.
However, we did find that the screen was near impossible to see when wearing sunglasses; not a problem that should trouble us Brits much, at least.
Music fans haven’t been ignored either. You get full support for Hi-Res audio playback, for enjoying top-quality tracks, while the Zenfone 4 also offers Bluetooth 5 connectivity. This means you can hook up to two separate speakers or headphones at the same time, handy when travelling with a partner. Asus has also served up some manual audio controls in the form of the AudioWizard, which can tweak the output based on your type of headphones and plenty more besides.
You get 64GB of storage on board the handset, of which just over 50GB can be used for your apps, media and everything else. You can also plug in a microSD memory card (in the second SIM card slot), to expand by up to 2TB. That’s something not offered by the OnePlus 5.
The spacious display is sharp, bright and offers full manual control over the colour output. You also get Hi-Res audio support, plus expandable storage for carrying a massive media collection.
We’d have liked a schedule function for the blue light filter mode, but besides that, we can’t really argue.
Features and OS
Android Nougat is overlaid with Asus’ own ZenUI software, which significantly changes the look and feel of Google’s OS while adding a fair bit of bonus functionality.
While the core structure of Android remains intact, Asus has replaced the fonts and icons to give the operating system a unique appearance. You can edit most aspects of the UI design by flicking a finger up your desktops, which opens the ‘manage home’ menu. This gives access to wallpapers and themes, as well as the ability to tweak the grid layout, scroll effects, font sizes and colours, folder sizes and so on.
The scope of the Zenfone 4’s customisation is impressive, matched by few other phones we’ve recently tested. Hell, you can even share your ZenUI setup with other Zenfone owners, if you like.
As well as standard Android features such as split-screen mode, the Zenfone 4 also serves up plenty of extra functionality; although a lot of it is buried away in the settings menus.
Elderly users or anyone who needs an extra helping hand can activate the nifty Easy Mode, which delivers a simplified interface with large, clear icons for the most-needed functions. The ZenUI Safeguard feature is also a worthy addition, offering a quick SOS alert to be sent to preferred contacts, as well as full location reporting. Of course, the Zenfone 4 isn’t an obvious choice for this user base all the same; we’d point to Doro’s handsets instead.
Meanwhile parents will appreciate the awesome Kids Mode, which can prevent your nippers from accessing certain phone features when they’re bingeing on Peppa Pig. Definitely a good thing.
Asus’ Customised Settings also delivers quite a few extra tools. You can sign in with two different accounts on the likes of Facebook, for instance, or stream your mobile gaming session straight to Twitch. Frankly, there’s so much to cover that we’ll end it there. Needless to say, the Zenfone 4 offers a broad range of bonus modes, most of which will be useful to specific user bases.
However, while you’ll (eventually) find a fair few decent features tucked away inside of ZenUI, the software is quite badly laid out and basically unintuitive. You’ll have to really go hunting to find some of the coolest additions, which makes this phone better suited to technically confident users.
We also noticed a few little bugs and issues during everyday use. For instance, copying files to a Macbook proved impossible as we couldn’t switch the Zenfone 4 from USB charging. We also struggled to sign into some WiFi networks as the authentication option never appeared. Hopefully these are the kinds of issues that will be sorted in software updates.
Lots of unique, well-considered bonus modes and impressive customisation helps the Zenfone 4 to stand out from a lot of its rivals.
The sheer number of extra features could prove confusing for anyone not already comfortable with smartphones, although many of the bonus modes are at least explained the first time you use them. You’ll just need to hunt them down in the Zenfone’s settings first. We also saw a few little software bugs, which proved rather annoying.
Performance and battery life
While the Honor 9 packs Huawei’s highly capable Kirin 960 processor and the OnePlus 5 sports the beefy Snapdragon 835 chipset, Asus has gone for the more modest Snapdragon 630 platform. This means the Zenfone 4 isn’t as powerful as its competition in this price bracket.
We saw plenty of little stammers here and there in our week of testing; usually a pause of a second or two when opening apps. Our review handset also crashed a couple of times, often while using the camera, which to be fair may be down to the software rather than the hardware.
On the whole however the Snapdragon chipset can handle everyday use, with games and other quite demanding apps running smoothly enough. Plus, resource management plays a large part in keeping the Zenfone running smoothly.
For instance, Asus’ OptiFlex feature allows you to prioritise your favourite apps, allocating more processing power and memory to ensure a swift experience. You also have the Mobile Manager app which can clear the phone’s memory cache and wipe junk files from storage. This app can even track your data usage and warn you when you’re approaching your monthly limit.
Battery life is certainly more impressive, thanks to the energy efficiency of the Snapdragon 660 platform and Android Nougat. After a bedding-in period, we found we could get well over a day of life per charge, often stretching towards 48 full hours. That’s with a reasonable amount of camera use, web browsing, media streaming and the rest.
Thankfully the Zenfone charges quickly too, using the bundled Type-C charger.
The Snapdragon 630 is energy efficient, so you’ll happily get a full day of use per charge, and often close to two.
Sadly the Zenfone 4 can’t come close to matching the performance of many rivals including the OnePlus 5 and Honor 9, which cost the same or less. That means it will be less future-proof as well as generally slower.
One of the stand-out features of the Zenfone 4, and the one which Asus is making the most noise about, is that dual-lens rear camera. Understandably so, too. You get a very similar setup to the excellent LG G6 optics, with a 12-megapixel f/1.8 aperture lens and Sony sensor backed by a secondary 8-megapixel wide-angle snapper, offering a 120-degree view of your surroundings.
We’ve fully tested the Zenfone 4’s camera tech so check out our in-depth Zenfone 4 camera review for all you need to know, as well as plenty of samples.
App and features
Although you can open the camera app at any time from your desktops or apps tray, Asus has also added a shortcut feature for those spontaneous snaps. If your phone is hibernating, just double-tap the Zenfone’s volume down or up button and you’ll be thrown straight in, ready to take a shot or shoot a video. This takes roughly a second or two from the button push.
The first time you boot up the Zenfone 4’s camera app, you might be a little intimidated. That’s mostly thanks to the rather large number of on-screen toggles and other virtual buttons, spread across the edges of the interface. Thankfully a few minutes of play time is all it takes to fully understand what’s going on.
All you’ll really need to crack on are the buttons along the right edge, when the Zenfone is held in portrait mode. As well as the shutter button for taking snaps, you’ll find the video button (which instantly starts a recording when tapped), alongside toggles for switching between the two rear lenses as well as the rear and front-facing cameras.
Those rear lenses work independently, so you’ll need to choose which one is best for the given situation. Thankfully that’s pretty easy. For most situations, you’ll want to stick with the more capable main lens; the wide-angle snapper is best for shooting a vista or large monument, which can’t be fully captured by the primary shooter. Flicking between the two only takes a second with the toggle button, and you can obviously check out a preview on-screen before committing to a shot.
Along the left edge of the Zenfone 4’s camera UI are a bunch of other toggles. Here you can activate the two-tone LED flash and a timer function, flick off the HDR mode (which helps out with high contrast scenes, while adding an extra bit of processing time to your shots), and change the aspect ratio. You can also turn on the Portrait mode from here, which is supposed to help your subject to stand out by blurring the background while keeping them sharply in focus; a common feature for dual-lens cameras.
Asus has also added full manual controls, if you fancy yourself as a bit of a photography pro. These are also accessed via the main camera screen. As well as a spirit level, the Pro mode offers control over the ISO levels, white balance and so on, via easy-to-use virtual dials. You can swap between the two lenses as before as well.
Flick your finger up the screen and you’ll be into the bonus camera features. This allows you to capture a GIF, shoot a timelapse or slow-motion video and so on. Alternatively, a flick down brings up a selection of filters, for changing the look of your photos.
After a few days of camera testing, we were certainly happy with the Zenfone 4’s photo output. We rarely had to throw away a shot because it was blurred or otherwise unusable, helped along by the built-in Optical Image Stabilisation which keeps things sharp.
With a standard 16:9 aspect ratio, your photos are captured by the main lens at 9-megapixels. That’s plenty of detail to ensure your memories look crisp and attractive when you get a TV slideshow on the go. Colours are pleasingly vivid, without appearing unnatural. However, high contrast situations aren’t handled too well by the HDR feature, as too much light is often sucked in. The result is blown-out, oversaturated areas; so the likes of a bright, sunny blue sky will appear mostly white.
Moving subjects are well handled as long as they’re not too close. The shutter speed is pretty quick and you can burst shoot up to 100 photos simply by holding down the capture button.
Swap to the wide-angle camera and you’ll capture shots at 8-megapixels. The 12-degree view is well suited to tourism, particularly when you’re attempting to shoot a large, complex scene. The results are a little different to the standard lens, however. We found that less light is grabbed thanks to the smaller aperture of this lens, which means that your photos will be a little darker. On the flip side, oversaturation is much less likely.
A photo shot with the standard Zenfone 4 camera lens…
And with the wide-angle lens…
At night, the Zenfone 4 more or less holds its own. In seriously low light the HTC U11 and OnePlus 5 produce less grain, although the Zenfone isn’t far behind. Of course, you’ll want to make sure your subject is as still as possible, otherwise they’ll appear blurred.
Asus Zenfone 4 photo samples
You can see a selection of our other test photos shot on the Zenfone in the gallery below.
By default, the Zenfone 4 shoots Full HD resolution video at 30 frames-per-second. However you can bump this up to 60 frames-per-second for a super-smooth finish, or even jump to 4K Ultra HD resolution.
Our test videos came out well, with solid image and audio capture. The lens effectively deals with sudden changes in lighting and focal points, while even distant sounds are clearly recorded. Of course, you still get some issues with oversaturation on bright days.
Electronic Image Stabilisation (EIS for short) helps to keep your video judder-free when you’re moving and recording at the same time. This is more effective at the default resolution and frame rate, although still functions at 4K and does a respectable job too. There’s an occasional popping effect when moving, where the image very briefly warps, although it’s nothing too serious. We’re happy enough with the results, especially as our video doesn’t feel as mechanically produced as footage shot on the OnePlus 5.
Asus Zenfone 4 video samples
Around the front of the Zenfone 4 you’ll spy an 8-megapixel selfie camera with an f/2.0 aperture lens. This packs almost as many bonus features to tinker with as the rear camera, so can do much more than simply snap your mug.
That selfie snapper is solid for everyday use, capturing sharp, naturally coloured photos in typical conditions. You do get a fair bit of oversaturation when shooting against a bright sky however, so you’ll have to be smart with your positioning.
In dark environments you can turn on a ‘screen flash’ mode, which lights up the display in order to brighten your face. This works okay, although does tend to make us look like ghosts, thanks to our super-pale skin. Plus, the camera is actually pretty good in low light without the flash, picking up a surprising amount of detail without too much grain to ruin the results.
You can also shoot up to Full HD video, if you’re into vlogging your life.
As with the rear camera, you can shoot a GIF animation to share online. Once again you have the Portrait mode, HDR support and a timer function, although the Pro mode has been replaced with a Beautify function. This allows you to tweak everything from your face shape and skin tone to your eye size with a series of virtual dials. You’ll see the results in real time, ahead of taking the photo.
As usual, these beauty shots are more freakish than gorgeous. With the settings boosted, we resemble plastic alien sex dolls rather than human beings. Still, the skin smoother function does at least remove those wrinkles if you want to appear fresher on those social media posts.
You can also apply these beautify effects to your photos after they’ve been taken, inside of the Asus photo gallery app.
Asus Zenfone 4 unboxing, setup and hands-on review
Check out our full 20-minute hands-on review of the Zenfone 4 right now, over on our YouTube channel and below. This gives a close-up look at the hardware as well as an in-depth exploration of ZenUI, plus a full tour of the dual-lens camera and its features.
The Zenfone 4 is one of the best smartphones that Asus has launched to date and it’s great to see the company’s handsets hitting the UK with gusto. However, can the manufacturer best known for its laptops and computing gear really do enough to sway consumers from the likes of the OnePlus 5?
Certainly there are plenty of great software features packed inside Asus’ ZenUI, which will particularly please parents and anyone who demands complete customisation. Meanwhile that dual-lens camera is good enough to create attractive long-lasting memories and boasts a solid wide-angle feature, making the phone a worthy consideration for Instagram obsessives. Media fans are also well catered for, in pretty much every department.
Still, the lack of serious power is a let-down, as the competition offers a lot more grunt for the same (or lesser) cost. Plus, the ZenUI overlay is a little buggy and quite poorly organised, which means many users likely won’t find some of the useful features buried within. It’s here where rivals steal the Zenfone’s thunder and make it a less essential purchase.
The Zenfone 4 launches in the UK in November 2017 and can be had SIM-free for £450/$585.