ASUS Zenfone Zoom review by

ASUS Zenfone Zoom review by

After a successful run with the Zenfone 2 series in 2015, ASUS is making smartphones to target specific user segments, like the mega-storage 128GB Zenfone 2 Deluxe, the mega-battery Zenfone Max (5000 mAh). Here in this review, a smartphone with 3x optical zoom with no external moving parts, unlike previous Samsung smartphone attempts.

With the official media launch announcement in Singapore on 2 March, here is a detailed review of the Zenfone Zoom ZX551ML with 4GB RAM and 128GB internal storage, describing my personal user experience over the span of 2 weeks.


Before you read on, check out my first-ever unboxing video created in collaboration with StarHub Community.

Design and UI

ASUS Zenfone Zoom review by

The Zenfone Zoom is the most premium-designed ASUS smartphone in recent memory. Its aluminium edges finishing reminds me fondly of the HTC One M8, while the rear casing is fitted with genuine leather, though it almost doesn’t feel like one (I had to confirm by smelling it).

ASUS Zenfone Zoom review by

The Zenfone Zoom also sports a strap loop and the retail package also comes with a leather strap. To further add to the photographic experience, there are dedicated hardware buttons for shutter and for video capture. You can configure to press the buttons either to launch the camera app, or to launch and capture immediately.

ASUS Zenfone Zoom review by

The review unit I received is running on Intel Z3590 (quad-core 2.5GHz), an upgrade from Zenfone 2 ZE551ML, 4GB LPDDR3 RAM and 128GB eMCP internal memory (faster than eMMC). Zenfone Zoom is the only other model apart from Zenfone 2 ZE551ML that has NFC. Similarly, the Zenfone Zoom comes with premium hardware specs like Wi-Fi 802.11ac (433Mbps), LTE Cat 4+ (250Mbps). What’s missing is dual SIM that is available in almost all Zenfone models in 2015.

ASUS Zenfone Zoom review by

The ZenUI on the Zenfone Zoom is similar to other Zenfone 2 smartphones, and it works smoothly without any lag or stutter. Personalisation is easy with themes and icon packs. You can even choose whether the launcher has an app drawer (like Android) or without (like iOS). There are dozens of ASUS apps pre-installed – photo editing, photo collage, movie collage, data manager – so that you do not need to find third party apps.

ASUS Zenfone Zoom review by


ASUS Zenfone Zoom review by

ASUS is the first company to put an 3x optical zoom (28 – 84mm, f/2.7 – 4.8) with image stabilizer into a smartphone without protruding lens barrel. Prismatic zoom lens design is not new. Many waterproof and shockproof compact cameras (like Olympus TG-870) employ such a design so that the camera lens can zoom in and out optically without exposing moving parts and ensure they are watertight. The technical feat is to build this smaller, and it took ASUS over a year since its bold announcement in 2015 to make it a reality.

ASUS Zenfone Zoom review by

Zoom action is smooth, with useful haptic feedback when it reaches the end of the zoom. The OIS (optical image stabilizer) helps to reduce blurry photos, though it still cannot prevent subject movements or chronic handshake syndromes. For full shooting controls, there is the manual mode where users can adjust focus, shutter, ISO, EV, WB. Zoom also works when shooting video, and I like how the brightness level remains constant even when zooming in and out. At widest angle, the camera can focus from 5cm, while at the telephoto end, you need at least 30cm distance.

ASUS Zenfone Zoom review by

Image quality retains the ASUS PixelMaster style. There is a good balance of noise and details, which I prefer against over-processed smudgy images by some other makers. There is little chroma noise at high ISO, but in certain lighting situations, like shooting in clear sunny day, I observe slight purple fringing at the image corners, albeit only noticeable when pixel-peeping.

After all the hype created by ASUS, consumers naturally expect the image quality to be spectacular, but the truth is that it can never match mirrorless or DSLR, because the image sensor size (1/3-inch) is still very small. And like most compact zoom cameras, the relative aperture changes when zooming in. This constraint may be crippling when capturing fast-action or in low light situations, but an experienced photographer would understand the benefits of a zoom lens which, in many situations, offer a better visual perspective.

How does the zoom create different perspective? See the following video and photos:

ASUS Zenfone Zoom review by
Photos taken from a distance zoomed-in is less distorted.
ASUS Zenfone Zoom review by
Portraits at 3x zoom does not distort facial features (although I do look slimmer – albeit larger nose – at 1x zoom!)

There is no doubt that optical zoom lets me get closer to details. With other smartphones, I would never have composed some of the photos using digital zoom, because they will look pixelated.

Here are unedited sample images shot without zoom, then with 3x optical zoom. I also included “12x” digital zoom, or rather, 4x digital zoom from the 3x optical zoom.

With the Zenfone Zoom, I can finally go on a vacation without the need of a compact zoom camera just because I needed to take close-up scenery!

Speaker and Headset

It appears ASUS is trying to create a more “audiophile-centric” sound. Instead of jarring treble, the Zenfone Zoom is tuned with a more balanced tonality. The unit is fitted with a 5-magnet speaker with larger sound chamber. The result is a warmer sound with more presence in mids which is great for listening but fails to stand out in the crowd due to its less piercing highs. Similarly, its accompanying headset is tuned with stronger bass presence that overpowers the highs.


The 3000 mAh battery life appears to be similar to the Zenfone 2 ZE551ML. For my kind of usage, it lasts about 14 hours, good enough for my full work day. The great thing is the Zenfone Zoom can charge in super speed (60% in 39 mins) with BoostMaster or Qualcomm Quick Charge chargers, just like Zenfone 2 ZE551ML.

The Target Segment: Who Should Get Zenfone Zoom?

ASUS Zenfone Zoom review by

ASUS has provided an important shooting feature that consumers with photography knowledge would appreciate. ASUS is also aware that not everyone will appreciate zoom cameras, so they are targeting to a “niche” group of camera-savvy consumers, and not expecting it to be massively popular like Zenfone 2 ZE551ML where it recently won HWZ Tech Awards Editor’s Choice for Best Mainstream Smartphone. If your kind of photography is mostly low-light wide-angle snaps (like restaurants, group selfies), then the Zenfone Zoom might not offer any additional value.

Would I recommend it? The Zenfone Zoom is practically a 2-in-1 device with features of a capable zoom camera and a powerful smartphone without adding much weight. I know the benefits and constraints of shooting with “kit zoom lens” and so my answer would be “yes”.

Without a doubt, many photography enthusiasts would lament why ASUS did not develop a brighter zoom lens module. I feel that for the cost that it would incur and the price tag that it would have to slap, this “better” product would result an even greater disappointment and criticism. This dream product would either require a larger image sensor or larger lens elements, resulting in a heftier smartphone.

Don’t get it because you hope it captures better images than other smartphones. Get it because it does capture better close-up images than any smartphone.


Platform: Android 5.0 (Lollipop) with ASUS ZenUI
Color: Black/White
Dimensions (WxDxH): 158.9 x 78.84 x 5 ~ 11.95 mm
Weight: 185 g (with battery)
CPU: Intel® Atom™ Intel® Atom™ Quad Core Z3590 (up to 2 core running at 2.5GHz)
Memory: 4GB LPDDR3 RAM
Storage: 128GB eMCP Flash, 5GB free lifetime ASUS WebStorage
Memory Slot: MicroSD card (up to 128 GB)
Modem: Intel 7262
Connectivity: WLAN 802.11 a/b/g/n/ac, USB, Bluetooth V4.0+EDR , NFC, One Micro SIM card
Network Standard: UMTS/WCDMA/FDD-LTE
Data Rate:
HSPA+: UL 5.76 / DL 42 Mbps
DC-HSPA+: UL 5.76 / DL 42 Mbps
LTE Cat4:UL 50 / DL 150 Mbps
2G : 850MHz/900MHz/1800MHz/1900MHz
3G : WCDMA 850MHz(5)/850MHz(6)/900MHz(8)/1900MHz(2) /2100MHz(1)
4G : FDD-LTE: (TW/JP version) 2100MHz(1)/1900MHz(2)/1800MHz(3)/850MHz(5)/2600MHz(7)/900MHz(8)/1800MHz(9)/800MHz(18)/850MHz(19)/700MHz(28)
Display: 5.5inches, Full HD 1920×1080/403 PPI, IPS, Corning® Gorilla® Glass 4
Battery: 3000 mAh Li-Polymer (non-removable)
Front 5 Mega-Pixel, Wide View, PixelMaster, Selfie Panorama (up to 140 ˚)
Rear 13 Mega-Pixel, 0.03 second laser auto-focus, Close-up macro photography (5 cm), PixelMaster, dual-color Real Tone flash, 10 -element HOYA lens
Audio Slot: 3.5mm
Sensor: Accelerator/E-Compass/Gyroscope/Proximity/Ambient Light Sensor/Hall Sensor

Availability from 10 Mar 2016

The Zenfone Zoom 64GB retails for S$659 (without mobile contract) and is available exclusively with StarHub Online Store on 10 March. Purchase with a StarHub Mobile postpaid 24-month contract to enjoy lower handset price between S$0 (4G 5 upwards) and S$449 (4G 300M).

Product website:


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ASUS Zenfone Zoom ZX551ML
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