The ASUS Zenfone 8 Hands-On Review: A New Compact Direction

Today ASUS is launching their new mainstream line-up of flagship devices, the Zenfone 8 series. Unlike last year’s iteration of the Zenfone 7 which was defined by the flip-camera design, ASUS is mixing up the formula this year with the new Zenfone 8, a completely different phone in a completely different form-factor, targeting a niche in the market which ASUS sees as an opportunity to differentiate itself in.

The Zenfone 8 is defined by its size: with a 5.9” screen and a width and height of 68.5 and 148mm, it’s by far one of the smallest flagship SoC powered devices in the market. It’s an extreme departure from the Zenfone 7 – however ASUS also introduces the Zenfone 8 Flip, essentially a Snapdragon 888 upgrade over what we’ve seen in the Zenfone 7, though this variant of the Zenfone 8 will be limited in terms of market availability, and today’s article will focus on the smaller Zenfone 8.

ASUS ZenFone 8 Series
  ZenFone 8 Flip

ZenFone 8

SoC Qualcomm Snapdragon 888 
1x Cortex-X1 @ 2.84GHz
3x Cortex-A78 @ 2.42GHz
4x Cortex-A55 @ 1.80GHz

Adreno 660 @ 840MHz

DRAM 6 GB LPDDR5 6/8/16 GB LPDDR5
Storage 128GB UFS 3.1
+ microSD
128/256GB UFS 3.1
Display 6.67″ AMOLED
2400 x 1080 (20:9)
90Hz

200Hz Touch

5.9″ AMOLED
2400 x 1080 (20:9)
120Hz

240Hz Touch

Size Height 165.08 mm 148.0 mm
Width 77.28 mm 68.5 mm
Depth 9.6 mm 8.9 mm
Weight 230 grams 169 grams
Battery Capacity 5000mAh

30W charging (PD3.0)

4000mAh

30W charging (PD3.0)

Wireless Charging
Rear Cameras
Main 64MP IMX686
0.8µm pixels (1.6µm 4:1 16MP)

f/1.7

64MP IMX686
0.8µm pixels (1.6µm 4:1 16MP)

f/1.7 w/OIS

Telephoto 8MP
3x optical zoom

f/2.4

n/a
Wide 12MP IMX363
1.4µm pixels Dual PDAF

113° FoV ultra-wide
f/2.2

Extra
Front Camera Flip-camera Design
Front cameras = Rear cameras
12MP IMX663
1.22µm
I/O USB-C USB-C
3.5mm headphone
Wireless (local) 802.11ax WiFi-6
Bluetooth 5.1 LE + NFC
Other Features Triple-function Power Button w/ Capacitive Fingerprint Sensor IP68
Dual Speakers
Under-screen fingerprint sensor
Dual-SIM Dual nanoSIM
Launch Price 21,999 TWD
(USD~748, EUR~626)
starting 599€

The Zenfone 8 and 8 Flip are powered by the new Snapdragon 888. We’ve reviewed the SoC quite extensively over the last few months in a wide range of devices from various vendors – the chip is characterised by increased performance coming at a cost of quite higher power usage due to the shift to a regressed 5nm process node.

ASUS equips the Zenfone 8 from 6 to 16GB of LPDDR5 RAM depending on the SKU model you chose, and comes equipped with 128 or 256GB of UFS 3.1 storage, with no microSD option this time around.

As noted, what really differentiates the Zenfone 8 from its predecessors as well as from other smartphones in the market is its more diminutive stature. At 148 x 68.5 x 8.9mm and only 169g weight, the Zenfone 8 is one of the smallest phones in the market, especially amongst devices powered by the latest flagship hardware internals.

ASUS states that this was a deliberate market positioning that they are experimenting with: the company has seen that while there’s tons of competitors in the now regular “larger” form-factor of phones, there’s actually very little options when it comes to smaller devices. Sony’s Xperia 5 series was one of the rare ones out there with a phone width below 70mm, however many people didn’t like Sony’s extremely elongated aspect ratio, and ASUS pointing out that the Zenfone 8 is now also the only option out there with a device height of below 150mm.

ASUS’s strategy here is I think excellent, and allows them to fill a niche in the market and compete for customers who are looking for such devices. The ergonomics of the Zenfone 8 are generally excellent due to its smaller size, but ASUS also designed the phone to have good in-hand feel due to the curved back glass design as well as the rounded metal frame of the phone.

The build quality of the phone is excellent, and I particularly notice the removal of the plastic “gasket” piece between the phone frame and the display glass that’s usually found on cheaper devices in the market.

The screen itself is a 5.9” OLED with 2400 x 1080 resolution, with an upgraded refresh rate of up to 120Hz, and a touch input of up to 240Hz. Unfortunately there is no variable refresh rate here, neither software nor hardware, so anything above 60Hz comes at the cost of battery life.

The Zenfone 8 uses a “regular” hole-punch front camera module instead of a mechanical flip mechanism of the rear cameras, which is completely fine due to the design limitations of such a much smaller device. I found it a bit weird that ASUS adopted this metallic ring design around the camera – I’ve seen it used before on other devices and I was not fan of it as it really draws the attention to the camera instead of making it inconspicuous. At least here on the Zenfone 8 it’s centred perfectly within the display hole.

The camera setup on the Zenfone 8 is extremely simple: it features the same main camera and ultra-wide module as found on last year’s Zenfone 7 Pro series, meaning a 64MP IMX686 main camera module that bins down to 16MP 1.6µm in regular auto mode pictures and features a f/1.7 optics with OIS, and a 113° UWA module powered by a 12MP IMX363 and f/2.2 aperture with autofocus capabilities. Generally we were not very impressed with this camera setup on the Zenfone 7 last year, and have similar low expectations of the Zenfone 8 – we’ll quickly check out some samples later in the piece.

The bottom of the phone features your typical SIM tray, which this time around does not feature a microSD anymore, USB-C port, as well as a good quality main speaker. Between the USB port and the speaker hole there’s actually also a small LED notification light – something that over the years has seen been deprecated by various vendors in favour on always-on displays. I greatly appreciate this feature as it’s much more power efficient compared to AOD notifications.

At the top of the phone, we find the mythical and elusive 3.5mm headphone jack. Over the many years we see countless vendors drop the feature and trying to promote wireless headphones which cost, more, have worse audio quality, and are prone to degradation due to batteries. Sony and ASUS are two vendors who did drop the headphone jack in the past and reintroduced them in subsequent generations due to negative feedback, so I applaud ASUS for also including it here on the Zenfone 8.

What’s new for ASUS, is the Zenfone 8 is an IP68 rated device, which was one feature limitation of the mechanical flip-camera design of the Zenfone 7, and continues to be so for the Zenfone 8 Flip.

Today’s hand-on review focuses around the Zenfone 8 as that’s what ASUS had sent out as samples, but the company is also launching the Zenfone 8 Flip. This phone is essentially identical to the Zenfone 7 with the exception for the upgrade to a new Snapdragon 888 SoC. Unfortunately, the 8 Flip will see a much more limited release compared to the Zenfone 8, notably with it not launching in the North American market.

System performance of the Zenfone 8 should be quite good virtue of the new Snapdragon 888. On top of that, ASUS’ 120Hz mode and 240Hz touch input rate should result in extremely fluid and responsive experiences.

One thing I have to make note of here is ASUS’s refresh rate modes. By default, the phone comes in the “Auto” mode, which in my experience simply switches between 90 and 60Hz depending on the application. I’ve never actually seen 120Hz used by the phone anywhere in this mode, which is odd. Besides the Auto mode, you can also explicitly set the phone to 120Hz, 90Hz or 60Hz modes all the time. In PCMark and also many other generic applications, Auto mode will switch to 60Hz mode while browser activity will switch to 90Hz mode. I tested that, as well as the explicit 120Hz mode of the phone.

PCMark Work 2.0 - Web Browsing 2.0PCMark Work 2.0 - Writing 2.0PCMark Work 2.0 - Photo Editing 2.0PCMark Work 2.0 - Data ManipulationPCMark Work 2.0 - Performance

In PCMark which is a good representation of overall device responsiveness, we see that the Zenfone 8 tracks rather very closely to the performance of the Snapdragon 865 powered Zenfone 7, depending on the refresh rate. What’s actually a bit weird is that at 60Hz, the ZF8 is actually a bit slower than the ZF7, a point which I’ll come back to in a bit.

Speedometer 2.0 - OS WebView (64b)JetStream 2 - OS Webview (64b)

In the browser benchmark, which we’ve lately started from a clean slate due to the new 64-bit browser deployments on Android in the last few months which improve performance compared to past results, we see that the Zenfone 8 tracks closely to the Snapdragon 888 powered Galaxy S21 Ultra, which is expected.

Overall Device Experience – 120Hz Good, Everything Else Bad

At the 120Hz setting, the Zenfone 8 performs extremely well as is as responsive as any other device in the market. What’s actually very strange and extremely concerning for the ZF8 is all the other operating modes, such as 90Hz and 60Hz. For some reason, beyond just a slower refresh rate, these modes have seemingly increased input lag as well as just overall sluggish feel for the device. The 60Hz mode in particular is quite horrible – it feels as if ASUS is also modulating the input touch response based on the refresh rate. Generally speaking, for the best experience, you want to keep the phone in 120Hz always mode and avoid the Auto as well as the lower refresh rate modes.

GPU performance of the Zenfone 8 is interesting given that’s it’s currently the smallest Snapdragon 888 device we have at hand. We’ve had determined that the Snapdragon 888 is a quite power hungry SoC, so combining this with a smaller phone which has a lesser thermal envelope isn’t quite the recipe for success.

Basemark GPU 1.2 - Medium 1440p - Off-Screen / BlitGFXBench Aztec Ruins - High - Vulkan/Metal - Off-screenGFXBench Aztec Ruins - Normal - Vulkan/Metal - Off-screenGFXBench Manhattan 3.1 Off-screenGFXBench T-Rex 2.7 Off-screen

Throughout the benchmark scores, we can indeed see that while the Zenfone 8 outperforms the Zenfone 7 Pro quite easily when it comes to the peak performance, the new smaller phone actually regresses its sustained performance to below the levels of its predecessor once the device heats up and becomes thermally saturated. ASUS has quite reasonable thermals here and the phone doesn’t exceed 42-43°C peak skin temperatures which is a reasonable and good behaviour, it’s just that the resulting power levels here mean that the SoC and GPU have to throttle quite a bit.

The end results aren’t bad, and the phone is still plenty competitive, it’s just that it doesn’t really showcase any performance advantage over the last generation of devices.

The Zenfone 8 features a contemporary 4000mAh battery, which considering the size and 169g weight of the phone is actually quite respectable and competes well with other alternatives in the market.

The features that might impact the battery life of the phone are the Snapdragon 888 SoC, less efficient than its predecessor, as well as the 120Hz display which lacks any more advanced power management. The latter aspect of the phone can be quite negative – while the 60Hz mode of the phone has an underperforming base power consumption of 615mW, the 120Hz mode raises this to a rather eye-watering 783mW on a full black screen at minimum brightness.

Anecdotally speaking, I’ve seen vast power regressions on almost all Snapdragon 888 flagship devices this year, all except for Samsung’s S21 Ultra. The Mi 11, Mi 11 Ultra, OnePlus 9 Pro, ROG Phone 5 all exhibit quite bad base power behaviour, and the only difference to the S21 series is that Samsung employs Maxim PMICs and Broadcom WiFi solutions rather than Qualcomm’s own chips. I don’t know if there’s a correlation there or not, but the Zenfone 8 shows similar lacklustre efficiency.

Web Browsing Battery Life 2016 (WiFi)

In the web-browsing test in Auto mode which switches to 90Hz inside of the browser, the Zenfone 8 tracks rather closely to the Zenfone 7. The predecessor has a 25% larger battery, but also has a much larger display. The contemporary comparison to make is the smaller Galaxy S21 which lands ahead of the ZF8 even though it runs at 120Hz mode, and far ahead at 60Hz.

I’ll be updating the article with fixed 120Hz and 60Hz results for the ZF8 in the coming days.

PCMark Work 2.0 - Battery Life 

As noted in the performance section, “Auto” mode actually fixes itself to 60Hz in various applications, such as PCMark. The ZF8 here in its best-case scenario lands actually quite well in the relative positioning, meaning battery life in this mode is relatively competitive.

Again, I’ll be completing the result set with other refresh rate modes in the comings days.

Generally speaking, the Zenfone 8 finds itself in a tough situation when it comes to battery life. The 90Hz and 120Hz modes are really inefficient due to extremely lacklustre base power consumption behaviours. If you were to use your phone at very high brightness levels, the luminance power would vastly overcome that disadvantage and one probably wouldn’t notice the deficit as much, but at lower brightness levels, the phone would last much less than comparative devices.

The conundrum with this situation is that while 60Hz seems to be efficient for the Zenfone 8, it’s also not an as quite good experience when it comes to performance and responsiveness. So either you’ll have to deal with a responsive and inefficient device, or with an adequate battery life but sluggish feeling phone.

The camera of the Zenfone 8 isn’t something that I had particularly large hopes for, given the fact that it seems to have the same hardware setup as on the Zenfone 7, which showcased quite disappointing results in our dedicated review of that device. Bar any surprises by ASUS in terms of improved software image processing, we should see rather similar results.

For this piece, I’m keeping things simple and just showcasing sample images from the ZF8 – I’ll be following up with a larger camera centric article across all recent flagship phones in the market in a few weeks’ time.

 

In this first scene, we see rather familiar results reminding us very much of the images produced by the Zenfone 7 last year. The shots are characterised by a tendence to flatten out textures a whole lot, some kind of side-effect of ASUS’ HDR algorithm, I think. The scene ended up quite a lot darker than it actually was and there’s just a general lack of any small detail highlights throughout the scene.

While the phone lacks a telephoto module, it’s possible to get to reasonable quality 2x shots via the use of the native 64MP shooting mode of the camera – ASUS here actually uses this by default when going from 1x to 2x zoom mode, something a lot of vendors with similar high-res camera hardware seem to not always get right. The result isn’t great given the 0.8µm pixel size, with very little dynamic range and a lot of fuzziness, but it’s still higher quality than a digital magnification.

 

In this scene I’m again reminded of ASUS’s issue with dynamic range and the tendency to just flatten out luminosity across the scene, giving it a 2D look rather than preserving depth of objects.


 

Looking at the ultra-wide angle shot, the phone does alright with the colours but completely loses out texture preservation compared to the main camera, with a large amount of blurring of details.

Dynamic range continues to be an issue in most scenes with the camera just not being able to preserve depth of objects unless in the most forgiving lighting conditions.

Generally, we also see that the optics of the module doesn’t keep up with the 16MP auto mode results of the sensor, as we’re seeing hazing and ghosting around highly contrasting edges.

Colourful subjects have again the issue that there’s lot of gradations and details that are seemingly lost due to the processing.

ASUS has added auto-focus to the ultra-wide angle this year, meaning this module is now able to focus extremely close to subjects down to 4cm, which can actually give quite good results and is a flexible way to enable macro photography.

Functional, not competitive

Overall, the results of the Zenfone 8 camera are disappointing, but not surprising. ASUS’s phones in general have historically had lacking cameras and image processing that was not up to par with other flagship devices. The Zenfone 8 positions itself as a 2021 flagship phone, but its camera system is far from that. It’s functional for the occasional shot, but it’s pretty much outshone by essentially any other camera solution in the market, with very little silver linings in favour of the device.

If you’re looking for competitive cameras in a phone, the Zenfone 8 is not the device for you.

Today’s launch of the Zenfone 8 series is an interesting attempt by ASUS to position themselves in a gap in the market. The focus is clearly on the new Zenfone 8 which introduces as new smaller form-factor, and in many ways, it’s a unique device in the market because of that.

ASUS’s efforts in creating a smaller flagship phone work out well in terms of the actual form-factor and ergonomics of the Zenfone 8. The phone it actually reminded me the most of is the Pixel 5, both petite devices of similar dimensions, with the Zenfone 8 of course being built of more premium materials and having higher grade hardware components.

The display at 5.9” lands at a sweet-spot in terms of density for the 2400 x 1080 resolution. While we didn’t cover the matter in a dedicated section, I was actually impressed by the quality of the image calibration of the phone, allowing for near perfectly balanced white colour temperature in the settings, something many vendors struggle with. The 120Hz refresh rate of the panel is also great for general responsiveness of the device – however it comes at a cost of battery life.

While the phone has a 4000mAh battery, generally you can only expect good results in the 60Hz mode as like with many other devices this year, the Zenfone 8 features odd power consumption regressions. The 60Hz mode in turn comes at a cost of a regression of user experience that isn’t nearly as fluid as the 120Hz mode.

Performance of the phone is adequate, however aspects such as the sustained GPU and gaming performance of the phone, while adequate, isn’t the best due to the heavier throttling of such a smaller device.

Finally, there’s the cameras, and much like on the Zenfone 7 last year, it can be a deal-breaker for potential buyers. The camera hardware as well as the image processing just aren’t up to par with the competition. While the cameras are functional, they are well behind any competitor solution.

As we always say, there’s no bad product, just bad prices. In that regard, ASUS prices the Zenfone 8 at a very competitive 599€ starting price, which is far below the positioning of similarly specced competitors. The thing is though, is that while ASUS positions itself as a cheaper alternative, it also comes with quite a lot of drawbacks and compromises. Amongst the “small-phone” crowd, there’s really only the Xperia 5 III which isn’t available yet and comes at an eye-water 922€, or simply the Galaxy S21 which can be had today at 680€ – more expensive than the Zenfone 8, but also a vastly better device.

As we always say, there’s no bad product, just bad prices. In that regard, ASUS prices the Zenfone 8 at a very competitive 599€ starting price, which is far below the positioning of similarly specced competitors. The thing is though, is that while ASUS positions itself as a cheaper alternative, it also comes with quite a lot of drawbacks and compromises. Amongst the “small-phone” crowd, there’s really only the Xperia 5 III which isn’t available yet and comes at an eye-water 922€, or simply the Galaxy S21 which can be had today at 680€ – more expensive than the Zenfone 8, but also a vastly better device.

The Zenfone 8 Flip is quoted to start at 799€. Due to the meagre improvements of the Snapdragon 888 this year I would rather just advise to consider the Zenfone 7 at only 432€ right now if you’re after the flip-camera design, given that all other features and specifications between these two phones are the same.

Finally, there’s the continued issue of availability and limited releases depending on country and markets. I had asked ASUS about their recent track-record of having extremely slow roll-outs, with users sometimes waiting months to be able to purchase the phones in their specific region or country. Similarly, the Zenfone 8 series don’t have any concrete sell date or more specific pricing beyond the European start prices showcased in the above slide. ASUS had replied that they’re aiming to do better this year, but again shying away from disclosing any more concrete per-country availability information.

In that context, given the lack of availability dates as well as obvious better value competitor devices, it’s hard to recommend the new Zenfone 8 series phones – the company still has a lot of work ahead of it if it wants to be a contender in the mobile market.