Given the somewhat yo-yo approach Asus has taken with its Zenfone series over the years - the 2018 Zenfone 5 was a fine-but-whatever mid-ranger, the Zenfone 4 was overpriced and somewhat forgettable, while previous models introduced firsts but failed to impress the western market - it's an entirely pleasant surprise to see the Zenfone 6 go all-in for the high-end flagship position in its own unique way.

When Asus invited us to take a look at the Zenfone 6 a month prior to its launch event, we didn't expect it to feature a large notch-free screen, mechanised Flip Camera to counter the front/rear cameras conundrum - a really unique take in the world of slider phones, punch-hole selfie cameras and a glut of notched devices - and huge battery capacity featured alongside the top-end Snapdragon 855 processor.

Even more surprising is that Asus's so-called ZenUI is more-or-less dead; ZenUI 6 is more-or-less stock Google Android Pie with some additional camera controls and algorithm layers for dark mode and battery management. That, to us, really shows that Asus is looking to target the smartphone world anew, to attract a different audience of users who might otherwise be buying a Google Pixel 3 or Huawei P30 Pro.

Sure, the Zenfone 6 will still a relatively unknown proposition given the changeability of the company's output over the years, but we've been using one for a full week to let you know whether it can live up to its lofty potential or not....

Our quick take

The Asus Zenfone 6 is an unexpectedly impressive flagship from a company that's an underdog in the smartphone world. But just because Asus isn't a major player in terms of volume can't take away from what the Zenfone 6 represents: it feels like a reset; a fresh start for a company looking to attract a new audience.

No, you won't get some niceties such as an in-screen fingerprint scanner, waterproofing, fast-charging or more cameras for greater shooting versatility. Plus the Flip Camera has its share of compromises for the sake of being the best selfie camera you're likely to see (i.e. a lot of its rear camera capabilites are behind its competition).

But you will get a massive screen with no notch distractions, 2019's most powerful current Qualcomm chipset, huge battery capacity, a software solution that will be smooth and clean after a few update tweaks, and that quirky Flip Camera. 

It doesn't get everything quite perfect, though, and it might not sell in big volumes. But that's kind of besides the point - we love a turnaround story and Asus is right on the heels of exactly that with this new approach. Especially with a price of £499 making it cracking good value.

If its software is stable by launch then the Zenfone 6 might well be the surprise flagship success of 2019. 

Asus Zenfone 6 - 4.0 / 5

FORAGAINST
  • Big screen is notch-free and glorious
  • Huge battery capacity for decent longevity
  • Clean software experience is close to stock Android (less stable though)
  • Flip Camera has a lot of potential with motion tracking / night mode / high resolution and more
  • Flagship specification (SD855) for a sensible price
  • No in-screen fingerprint scanner and rear scanner is too small
  • Screen is LCD rather than OLED (an odd choice as there’s no hole-punch notch)
  • Flip Camera potential not fully realised
  • No Google Night Sight equivalent (Night Mode is ok
  • but not the same)
  • Smart Key positioned too high and lacks full customisation
  • Overzealous auto-brightness
  • Unstable software at time of review

No notch display

  • 6.4-inch IPS LCD 'all-screen NanoEdge' display
  • No notch, 92% screen-to-body ratio
  • 2340 x 1080 resolution
  • Gorilla Glass 6 front
  • 100% DCI-P3
  • 600 nits max

The Asus take on 2018/9's now well-established notch - that black-out area at the front of many current smartphones where the selfie camera is typically housed - is that it's just not necessary. It just takes a bit of creativity and a whole new camera mechanism - which we'll get to in a moment.

Asus Zenfone 6 lead image 2
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When the Zenfone 6 was first thrust into our hands it was impossible to ignore this giant-screened device's lack of front-facing camera distraction. It's a display-forward proposition with no notch and small bezels overall - we side-by-sided it with our P30 Pro and the 'chin' bezel is more-or-less the same, while the side bezels are perhaps a millimetre or so more on the Zenfone 6. All that makes the large 6.4-inch panel a dominant force thanks to that 92 per cent screen-to-body ratio.

As Asus has chosen to ditch the notch, however, there's one perplexing hardware choice in our view: this is an IPS LCD panel rather than OLED. Now, it looks totally fine, but a punch-hole notch solution would have to be LCD because of how the panel is cut. Surely Asus should have taken on the advances of an OLED panel - with richer blacks and more pronounced colours - to really show-off its notch-free solution? Plus, despite a quoted 600 nits brightness, we've found the auto-brightness to be stingy and lacking when it's sometimes needed, dropping to low levels unexpectedly.

When eyeing-up content particularly close the panel's Full HD+ resolution is plenty sharp. Sure, others go higher resolution, but there's an argument that it's nothing but detrimental to battery life, even at this larger screen scale. Sit the Zenfone 6 next to its notched competitors and it stands out in a largely positive light overall.

Asus Zenfone 6 details image 4
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There's no in-screen fingerprint scanner to be found here either, with Asus going somewhat old skool in its use of a rear positioned sensor. The positioning of this is fine enough, but the scanner opening is small and using it feels like stepping into the past. We much prefer the side-mounted solution on the Honor 20 Pro, for example, while the option of an in-screen scanner really doesn't seem like an impossibility to us.

Flip-up cameras

  • Pop-up mechanism with geared steps for full control through 180 degrees
  • Dual camera unit: 48MP standard (26mm) and 13MP wide-angle (11mm)
  • 48MP (Sony IMX586), f/1.79, 26mm equivalent
  • Laser autofocus, Dual Pixel autofocus sensor
  • 13MP (Omnivision), 11mm equivalent
  • Motion tracking & Panorama modes
  • 4K video capture (to 60fps)
  • No optical stabilisation

So what of the front-facing camera? Well, it's the rear camera. Only with the touch of a button in the camera app the rear unit - comprising a 48-megapixel sensor (which quad samples for 12MP shots), alongside an ultra-wide 13MP sensor - flips forward, hence its Flip Camera name.

We've never seen a solution quite like it; the closest thing is the Samsung Galaxy A80, but that phone's auto-slider mechanism and flip-around camera 'bar is binary, i.e. it's either facing forwards of backwards. Asus goes one better.

Flip Camera rotation and modes

This is where the Taiwanese company has really delved into its box of creativity. Not only does the Flip Camera rotate around on its hinge mechanism - it's fairly quick, we're talking maybe a third of a second to get into position, but doesn't feel quite fast enough - its gear system means it can also be step controlled throughout its 180 degree rotation to any angle that you wish.

Why would you want to control the camera in such a way? Well, there are lots of potential options here, some of which are realised within the app. Press-and-hold the selfie camera button and an on-screen slider appears, meaning you can position the camera at, say, 90 degrees for waist-level shooting - ideal for getting down lower to shoot scenes in a more square-on fashion or be at the level of animals and kids to shoot in a more creative way. However, there's no pre-set angles, like a 90-degree option, to select with ease - so we doubt many people will delve into this mode, nor is it easy to realise how it's controlled from the off.

Beyond that, Asus has also implemented a Motion Tracking mode which locks onto a subject and then physically moves the camera around in real-time to keep that subject in the frame as they also move. It works pretty well, too, although fast-moving subjects are outside of its capabilities - something we'd like to see improved upon.

Furthermore the Pano mode also takes advantage of the camera's rotating motion. You needn't pan your hands/body to take a panorama - simply hit the start button and the camera handles the rotation until you request it to cease, with up-to-180-degree panoramas in either vertical or horizontal format possible. It's kind-of trippy to use because it almost gives you that sensation of falling when looking at the screen, as it shows the movement despite your body being stationary.

However, Pano introduces some bugs as a result of this motion - we caught a hilarious shots with people walking through the frame and their legs ended up being stretched all over the show, like Stretch Armstong - but then no multi-frame sampling panorama mode is perfect. That said, we'd prefer to simply move our hands to take a panoramic shot as it's quicker and easier and we think the results are often better too. 

There's more too. Because the Zenfone 6 has a variety of sensors on board, including a gyro and proximity sensor, the device knows the camera's position and orientation at all times. Therefore it won't slam shut into your ear/hair when making a phone call, it won't pop out when the phone is flat on a table and see the device go crawling off onto the floor and smashing to pieces.

The Flip Camera even has a default defence mechanism if you drop the phone by auto-retracting in 0.1 seconds to ensure it's stowed and won't be damaged - something we tried out (nervously, in case we didn't catch the device) and found amusingly impressive. It's perhaps strange, however, that it can retract this fast but doesn't get into position as expediently for selfies. Asus says this is for the sake of longevity (the unit is tested to 50,000 cycles); not that it's a weakling anyway - grabbing the camera unit and moving it manually isn't what you're supposed to do, but it's not caused problems when we've been doing so.

A rotating camera does bring its share of burdens, though, including the fact that Face Unlock is so much slower that it's unlikely to ever be used. The mechanical process also means the gear system and motor makes a little bit of noise and some physical grinding in operation. You can add additional sound presets for added entertainment to mask this though.

The biggest downside of all, however, is that there's no optical image stabilisation. Asus is saying this feature would add physical constraints that wouldn't be possible to feature within the existing design. But it's a feature that most will expect - especially when same-price phones with more cameras, like the Honor 20 Pro, offer it as standard to assist in a variety of its shooting modes.

Asus Zenfone 6 camera image 2
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We also don't think the Flip Camera is fully realised in software terms just yet. The manual slider for rotation is too short and fiddly. The lack of preset positions - like we say: 90 degrees at a tap would be great - is a shame. And there's wider unrealised potential around third-party apps (there's no SDK is available so that's not possible at present). So while there's nothing else like the Flip Camera on the market, some more conventional solutions don't fall into the same set of criticisms. 

Image quality and modes

Having fancy modes is one thing, but what of the camera itself? Asus has opted for a dual sensor setup, the main sensor - a 48-megapixel unit sourced from Sony - offering a larger physical size, an interesting colour sampling methodology and wide f/1.79 aperture to up its quality potential; while the wide-angle lens opts for a 13-megapixel sensor with automatic barrel correction to keep shots looking less distorted.

Obviously 48 million pixels is one heck of a lot, but by default the camera shoots 12 megapixel shots. The reason is down to how this Sony sensor offers oversampling, whereby four pixels will become one in a final image - but can draw from wider information and neighbouring pixels to extract optimum detail, sharpening and colour. At least that's the theory. The full 48MP resolution is available, too, if you want to capture massive files, while the sampling method can also be utilised the other way by shooting multiple frames for 109 megapixel results (which are so huge they take a little while to load at full resolution on the Zenfone 6's screen).

Thing is, despite all the spec swagger, the Zenfone 6's camera just isn't that good most of the time. The processing over finer details leaves a lot to be desired - our shots at Red Rock in Nevada all lack real bite, with over-processed details - while lens flare is an issue, the wide-angle camera isn't wide enough, and low-light processing leaves everything particularly mushy.

Where the camera succeeds is when subjects are a little closer. Shooting a cactus reveals a lot more detail in its resolve; the same can be said of an owl-a-like moth that was perching in a window. Here the Asus camera shows its worth.

Asus Zenfone 6 review camera samples image 5
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Asus has pushed into some additional modes, with Night Mode being one such example. This functions much like Huawei's equivalent mode of the same name, capturing multiple frames at different exposure levels and combining them for a well-exposed shot even in the dead of night. Having shot a number of frames at Copenhagen Airport train station, however, it's clear to see this mode doesn't work nearly as well as the Huawei P30 Pro equivalent; the Asus' results are just too mushy and lacking in colour vibrancy.

Furthermore this Night Mode is no Google Night Sight, i.e. the Zenfone 6 can't shoot in very low-light conditions and magic exposure and colour detail out of nowhere like its Google competitor. Fortunately the Zenfone 6's fast aperture means shooting in dim conditions is little bother and the autofocus is decent enough - another benefit of that Sony sensor with on-sensor phase-detection autofocus pixels.

Ultimately, with many competitors now running with a 48MP sensor - from the Honor 20 Pro, Xiaomi Mi 9 , even cheaper models like the Moto One Vision - the Zenfone 6 establishes itself alongside those equivalents to some degree. But there's no stabilisation, processing is overworked for anything but near-by subjects, night shooting modes aren't that great and the wide-angle camera isn't wide enough and suffers badly from flare.

Asus Zenfone 6 review camera samples image 9
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Flip this around to selfie mode and the camera has the keys to great self-snapping quality. As the subject distance is perfect, the resolve here works a treat. If selfies are your all then there's a lot of benefit. But if you want to have the most capable rear camera, too, then the Zenfone 6 leaves more to be desired.

Flagship hardware and software

  • Android Pie 9.0 - Android Q & R updates promised
  • Smart Key to upper right (Google Assistant button)
  • Qualcomm Snapdragon 855 platform, 6/8GB RAM
  • Up to 256GB storage, microSD expansion
  • 5,000mAh battery capacity, 18W charge
  • Connectivity: LTE Cat 18, no 5G
  • 159.1 x 75.4 x 8.4-9.1mm; 190g
  • IP waterproofing rating lacks
  • Built-in 3.5mm jack
  • Stereo speakers

Compared to its Zenfone predecessors the Zenfone 6 dramatically changes its software approach too. Although Asus is still calling it ZenUI - here in its sixth iteration, ZenUI 6 - it's so far removed from what you might expect that to mean.

Stock Android solution

In fact, it's more-or-less stock Android with just some extras that are necessary for the camera and Smart Key controls (think of this as the Google Assistant shortcut key). We've long said that the earlier ZenUI formats were too heavy handed with different styles, pre-loaded apps and extras, which is completely removed in the Zenfone 6.

At first we found ZenUI 6 to be smooth and sleek. But since moving into the handset as our daily driver phone, we've found it to be less proficient than Android proper. Although Asus says it's shaved milliseconds off animation and loading times compared to Google's own, we've found some apps - like the Camera - to be slower to load compared to an older Google Pixel phone.

Asus Zenfone 6 Review Software image 1
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At present it's stability that's the Zenfone 6's main issue. We've had sequential crashes (not releated to auto software updates), corruption warning that have seen us fully reset the device and start again, apps fail to load without a full handset restart, and plenty of hangs and black-out app crashes (from AMEX to British Airways to Google Maps and more). All of this may be fixed with software patches but it's not as immediately perfect as we'd expected it to be.

There's so much good to be said about the theory of Asus' new software. But in practice it's way off the mark and needs a lot more stability work. We'll update this review as an when patches occur, in line with the phone's release date.

Beefcake battery

Beyond the software the Zenfone 6 is a fairly large scale phone. Inevitable given its 6.4-inch screen size, for sure, but also part and parcel of one of its other significant features: a 5,000mAh battery. Yep, Asus has gone large on that front, being the first manufacturer to pair such a capacious battery with the Qualcomm Snapdragon 855 platform (with 6GB RAM, or 8GB in the special edition that we're reviewing here).

To put 5,000mAh into perspective: the Huawei Mate 30 Pro has a 4,200mAh battery and it lasts an absolute age, to easily beyond one day. Take that into consideration and the Zenfone 6 - which uses a combination of Google's adaptive battery monitoring for individual apps, paired in hybrid with Asus' own OptiFlex algorithm solution - and we've found it to be of similar stamina, really, offering a hardcore day of use with around 30 per cent remaining by bedtime. It does go to show that less battery capacity can last just as long, though, as we were expecting the Asus to really own this category - not just match it.

Asus Zenfone 6 review software image 2
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That's pretty much unheard of in the flagship space. As is the 3.5mm headphone jack, which features on the bottom next to the USB-C port and dual speaker output.

But a big battery comes with some degree of compromise though. If you want fast-charging then the physical size of the battery has to be far bigger to accommodate swell thresholds and remain safe. Asus has avoided this by opting for an 18W charging solution - so it's a lot slower than the 40W Huawei SuperCharge that you'll find on the P30 Pro. But having heard Asus' reasonings for its selection we think its a fair compromise. After all, given how long the battery will last anyway, you're unlikely to be anxiously rushing to the plug socket during the day, so night-time top-ups are perfect for a device such as this.

Of course such a battery capacity requires physical space, but the Zenfone 6 is nigh-on identical to the Huawei P30 Pro in terms of dimensions. It's a tad thicker near the camera unit, but it's barely noticeable. It's not too big, nor too heavy and is part and parcel of buying a large-screen device with epic battery life.

Smart Key for Google Assistant

With Google Assistant becoming ever popular, Asus has a dedicated key - called Smart Key - for controlling the voice control assistant. That's not an uncommon feature - although others integrate it into the power button, giving dual functionality, which is a simpler solution - but why Asus has chose to position this key about as far away from a finger or thumb we can't fathom. It makes the Smart Key almost useless because one-handed use isn't really plausible.

That's a shame, as Asus has implemented some really nice tweaks over the standard Google Assistant use. For example, Private Listening allows Assistant read-back to occur through the speaker earpiece rather than aloud for all to hear; while Smart Volume is always monitoring the ambient sound in the room around to output sensible volume levels rather than ultra-loud and embarrassing ones. Great ideas.

Furthermore the Smart Key has its name because it can go beyond just calling Google Assistant into play. Asus calls it customisable, we'd call it semi-customisable because you can't assign specific app launches to it - only certain features such as, say, torchlight. More would be better, although, as we say, the position of the button is totally in the wrong place - it should be on the opposite side of the phone, where it would be reachable with ease - so it's largely irrelevant anyway.

To recap

An unexpected flagship from a company that's an underdog in the smartphone world. But just because Asus isn't a major player in terms of sales volume can't take away from what the Zenfone 6 represents: it feels like a reset; a fresh start for a company looking to attract a new audience. There's plenty of quirks to attract too, from the Flip Camera to the massive battery capacity.