Asus Zenfone Zoom Review: A technological achievement, with room for improvement

Bottom line is that while the Zenfone Zoom is quite an achievement, Asus really needs to lower its price tag to make it an attractive package.


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Asus smartphones are indeed not known for their cameras, with a majority of them being budget to mid-range. The Zenfone range provides decent image quality but do not stand a chance against flagship devices coming from Samsung, Sony or Apple.

So when we attended the launch even of the Zenfone Zoom, we really did not know what to expect from the smartphone's camera, but in our first impressions we were impressed with the set up and innovation that Asus has managed to pack into what appears to be a slim body for a camera smartphone with 3X optical zoom.

However zoom on a smartphone is not a first. For example, Samsung has been building smartphones with zoom lenses for quite some time now, with the last one being the Samsung Galaxy K Zoom that was priced at Rs 29,999 and soon after began retailing for Rs 19,999. The Samsung packed in a 10X optical zoom, but was more camera than a smartphone. Luckily this reviewer used to own the same, so we do know what one can expect and what one should not from the Asus Zenfone Zoom.

Build and Design: 8/10

 Asus Zenfone Zoom Review: A technological achievement, with room for improvement

We really like the build quality and the camera-centric design of the Zenfone Zoom. While we were taken aback by its heft, this is the first smartphone in the Zenfone range to pack in a metal frame made of aluminium alloy, so it does look premium with its rounded edges and well-finished buttons and an overall matte finish.

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What we did not like was the back. While we understand that a camera smartphone has to sport a good grip and be durable at the same time, the back of the Zoom, which sports a leather texture, made it look a bit budget. While Asus claims the back has a layer of leather, we had a tough time convincing people of the same in the office. Many were convinced that the back was made of plastic and the reason for this was that layer of leather was simply too thin and did not feel soft (which is what defines it) like what we had on the LG G4.  Still then, we appreciate Asus's attempt at going premium while being durable at the same time, because even with our rough usage, the leather remained pretty much intact without a single mark or scratch.

The front sports a 5.5 inch display with the receiver on the bezel above (flanked by the sensors on the left and the front-facing camera on the right) and the three standard capacitive buttons below that include the back, home and multi-tasking keys.

The left side remains clean with no cutouts or inserts, since the SD card and the micro SIM slot are located under the back cover (something that is pretty tough to open up).

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On the right side we have the volume rocker, power.unlock button, video recording button and the two stage camera button.

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On the top, there's just the 3.5mm headphone jack and the secondary mic, while the bottom gets space for an eyelet for the lanyard, mic and the micro USB port.

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On the back we find the prominently placed camera unit a metal cover that is painted in the top area, while the speaker sits at the bottom-left after the Asus logo and the hump.

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Overall, the design and colour choice of the Asus Zenfone Zoom did remind us of high-end point and shoots, with metal buttons that felt premium, had sufficient travel and provided proper feedback especially during camera operations. The two-stage shutter button was ideal for the camera and we were happy to see a dedicated button for video recording as well.

Features: 8/10

Being a camera smartphone, one would expect some stellar specs, and the Asus Zenfone Zoom certainly does not disappoint. On the front we get a 5.5-inch Full HD (1920 x 1080 pixels) display, with Corning Gorilla Glass 4 protection. Inside, Asus has packed-in a 2.5GHz quad-core Intel Atom Z3590 processor, which is accompanied by a PowerVR G6430 GPU. There's 4GB of LPDDR3 RAM and 128GB of internal storage along with support for  microSD cards of up to 128GB in capacity.

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The handset runs Android 5.0 Lollipop with Asus' ZenUI to keep things refreshed. In the camera department we get a 13MP sensor with OIS and 3X optical zoom thanks to the 10 element Hoya Lens set up with an f/2.7-4.8 aperture, Laser AF and dual-LED Real Tone flash. The lens arrangement is perpendicular to the plane of the smartphone and Asus as used stepper motors to ensure smooth noise free operation of the zoom mechanism.

Asus 3x

On the connectivity front, the Asus Zenfone Zoom delivers with a 4G LTE / 3G HSPA+ bands, Wi-Fi 802.11 a/b/g/n/ac, Bluetooth 4.0, GPS and NFC. All of the above is powered by a 3000mAh battery that comes with ASUS BoostMaster fast-charging technology.

Display: 7.5/10

The Zoom being a camera smartphone, we did expect the display to be spot on. The 5.5-inch Full HD IPS LCD display was sharp and showcased no jagged edges or pixelation, while viewing text and images. The display was legible in direct sunlight we could read text and view images comfortably.

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Asus' Zen UI provided a good level of tweaking inside the Screen color mode settings with the ability to choose from three presents (Balance, Bluelight Filter and Vivid) or simply go in for a custom mode where users can tweak the hue and saturation levels to their preferences.

We had an enjoyable experience while watching movies, but the glass screen was a bit too reflective for our liking.

Software: 7/10

Overall, we liked the software experience on board the Zenfone Zoom which packs in Android 5.0 Lollipop with Asus' Zen UI on top. The UX is stutter free and provides plenty of customisations. Similar to other Asus devices, the Zoom also allows for most of its apps to be updated individually via the Google Play Store. With this, the apps remain updated at all times and Asus seems to be continuously updating its native apps to ensure a refreshed UI that is completely customisable.

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From changing themes via the theme store, to the customisable lockscreen, down to the app icons (of native apps) that get updated (like Power Saver, Weather, Calendar) to display fresh information, Asus seems to have thought of it all. You can even change the fonts and adjust the display saturation to your liking. And there's more, Asus lets you manage the power, customise the functions of the capacitive touch keys and even record a call in progress without the need to download an additional third-party app.

The default launcher also got an update where a swipe down lets you do a search across contacts, apps and online and even shows you the recently used apps. Overall on the software on the Zenfone Zoom left us satisfied, while the hardware below kept it running flawlessly.

Performance: 7.5/10

While all the hardware specs did look great on paper, using the smartphone left us a bit disappointed. While the Intel chipset inside kept the software running pretty smoothly, we did come across a heating issue when using the camera. The smartphone did not heat up while taking test shots (which required some patience). But at an event or a party, which is when the camera app or the viewfinder remains on constantly the smartphone heated up after five minutes of use which was unexpected and lead to disastrous results while clicking photos (more on this in the camera section).

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Camera app aside, the apps ran smoothly and opened and closed without an stutter or lag. And while the same can be said about gaming, we did notice that the top bit of the smartphone did get warm, but not hot enough for us to keep the phone down. Overall, the Intel Atom Z3590 could run a bit cooler with some kernel tweaks but during our testing it did not turn out to be a problem.

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Watching videos worked flawlessly and the software helped by supporting plenty of formats. The loudspeaker on the back could have been a bit louder as we often found ourselves cupping the speaker while viewing videos without the bundled headphones.

Talking about headphones, the ones bundled in the package were pretty good. Audio quality coming from the smartphone while listening to music was great as well with balanced audio that is not too heavy on the bass notes. The receiver volume was sufficiently loud and we could hear the caller loud even in traffic. The same can be said about voice quality with the caller at the other end of the line being able to hear us loud and clear.

Camera: 8/10

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Considering the price tag that Zenfone Zoom retails at, we would have recommended the Samsung Galaxy S6 over it. But then again, it does not sport the 3X optical zoom that we have on the Zoom with a 10-element lens set up.

The complex technology aside, the zoom functionality works and it does so without any fuss. 3X zoom in terms of optical zoom is nothing much to talk about, most point and shoot cameras do offer a similar zoom level but in a much thicker package.

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While mistakenly placing two smartphones in one pocket, we managed put a nasty scratch not just on the camera hump but on the glass lens cover as well.

This is after all the first smartphone to feature a 3X optical zoom lens setup with OIS in a package that is just 11.95 mm thick. While most of our shooting was done in the Auto mode, we did not hesitate to shoot in manual with some interesting results. Simply put, we switched manual mode only when the lighting conditions were not right or the focus was not locking on to area that we desired (this turned out to be a problem in macro mode).


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In the auto mode we have the usual smartphone camera UI that has controls for the flash, camera switcher and the settings on the left of the viewfinder and the preview, Manual mode switch, shutter, video recording button, and the scene mode switcher when held horizontally.

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Tap on the manual mode switch and along with the standard set up from auto you get an additional layer of manual controls like white balance, exposure, ISO, and focus with the histogram showing at the bottom left of the viewfinder. Tapping on to any of the manual settings lets you expand them and adjust the same and then hit the shutter button to take your shot.

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Overall, the camera's interface is fun and simple to use and delivers great looking images but there one niggling issue. Our only problem with the manual mode was that changes made in manual mode, remained when we switched back to Auto mode as well. Hopefully, Asus rectifies this, as an Auto mode should be completely 'Automatic'. On the other hand, we really wished there was a way to save the custom settings (Custom 1, Custom 2 etc.) made in manual mode.

Image Quality

Starting with the pros, the images look great. They showcase the good colour saturation levels and pull off the same with little noise.

Note: Images have been resized below. To see the high resolution images please click on the images. Alternatively, you can also check out the Asus Zenfone Zoom album on Flickr







While the sensor seems pretty small at 13MP, Asus seems to have made good use of every pixel in its array. In Auto mode, we managed to get a decent amount of detail in day light and low light situations as well. Switching to manual however does plenty of justice here and you can get noise free images (provided you have a tripod) by slowing down shutter speed to 1 second and slower. It was possible to click good looking images in low light thanks to the 4-stop OIS, but you will still need steady hands. Still then the presence of OIS and the ability to manually bring down the ISO indeed delivers some crisp images with almost no blur or noise.


Image Shot at wide.


Image shot at 3x zoom.


Image shot at 3x zoom.

The zoom lens set up did a good job, but the images could have been a bit sharper at the far end of the zoom.

Surprisingly, even at full zoom, we managed to shift the manual focus accurately to exactly where we wanted as can be seen from the image below.


Image shot at 3x zoom.

The ISO levels thanks to the camera's Auto mode work overtime and this led to high levels of noise in images shot in bright day light and low light images as can be seen from the images below.


Image shot in Auto Mode.


Image shot in Auto Mode.


Image shot in Auto Mode.

Clearly, using this camera in Manual mode will see good quality images in every situation. But for that you need to keep a tab on the ISO setting all the time. And talking about the manual mode we managed to obtain some impressive low light imagery with the noise well under control as can be seen from the images below.


Image shot in Manual mode at ISO 50 and manual focus pushed to the background.


Image shot in Manual mode.


Image shot in Manual mode.


Image shot in Manual mode.

But we had a few issues as well. We noticed plenty of purple fringing around objects at the corner of the frame and there was also a level of softness in the same areas.



The macro mode in Auto was a bit problematic, like when clicking a pictures of flowers. We had a tough time getting the focus to lock on the right spot. Eventually we ended up switching to manual and we managed to focus on the area we wanted as shown in the images above.

Software and images aside, the display's ambient light sensor did not play nice in brightly lit shooting scenarios. For example its dims in bright sunlight, which often left us cringing at the viewfinder in brightly lit conditions. Eventually we gave up and manually cranked up the brightness of the display by turning off the auto-brightness settings.

What was a bit disappointing was the absence of 4K video. So we ended up with just 640x480, 1280x720 and 1920x1080 for video modes and there was no 60fps recording either. While the quality of video recordings were good and showed good colour accuracy and brightness, turning on Video Stabilization automatically turns off Full HD video recording, which was really not expected from a smartphone of this caliber.

Battery: 6.5/10

The 3000mAh battery inside the Asus Zenfone Zoom cannot be removed. This was a bit disappointing as for camera use, a removable battery that can be swapped makes a lot of sense. To make things worse, the camera will chew down your battery life since it is the main purpose of the smartphone. Thanks to the absence of a xenon flash we don't have a big problem.

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Still then, the battery life of the device as a smartphone was not too satisfactory and Asus could have gone with a bigger battery as a simple approach to solve the problem. With continuous flow of WhatsApp messages and 2 email accounts on sync, watching a few YouTube videos, locally stored content and  the battery could not get us through a work day. By the end of the day we had to plug it in.

But this where the Zen UI comes to the rescue with a variety of Power Saver modes. During our outing for the Camera section and on normal usage we ended up keeping the device on Power Saving mode as we were convinced that the battery could not make it too far. During the benchmark tests, the phone pushed us into activating the Performance mode. But fear not as we ran the benchmarks in both normal and performance and difference was nothing to talk about. But placing it in performance mode did drain the batter much faster. So it is not a good idea to place it in this mode especially when on trip or outing as 3G networks will drain it very quickly.

Verdict and Price in India

While Asus did advertise that the camera as capable of shooting DSLR-like images, the Zenfone Zoom clearly cannot come close to it. What it does creep pretty close to is standard point and shoot cameras with manual controls. However do note that we used the word "close".

This means that the Zenfone Zoom is not going to replace your camera. But it comes with one added feature that no other smartphone delivers, 3X optical zoom. More importantly, it delivers the same in a package that is not as thick as the Lumia 1020 nor the Samsung Galaxy K Zoom (both smartphones are not produced anymore).

Still then, in terms of ease of use and clarity of the camera Asus needs to work on the Auto mode to help it deliver better images; something that can be resolved in future software updates. Let's face it, not every one likes tinkering around with the manual modes. Coming to the competition, there is plenty and yes, they do a better job.

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The LG G4 for example now retails from Rs 36,000 and is lot lighter and produces some great-looking low light photos. There's also better video options on the same with support for 4K video, which is something that the Zoom lacks; and you also get a leather back cover. The only thing it lacks is an optical zoom which some may be fine with.

Next up in line would be Samsung's current flagships, the Galaxy S6 twins. They sport a fantastic cameras and deliver great low light shooting and 4K video thanks to the Exynos chipsets inside at a price tags that range from Rs 33,900 to Rs 40,900.

Bottom line is that while the Zenfone Zoom is quite an achievement, Asus really needs to lower its price tag (currently at Rs 37,999) to make it an attractive package. While the manual mode is really great and the 3X zoom impresses, the results are not as sharp at the far end of the zoom, which is something that the above two smartphone options surpass by a big margin. In short, buy it if you are an Asus fan or if you simply use the manual (or pro) mode, else there are better options that will get you better pictures at a similar price tag without all the hassle.

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ASUS ZenFone Zoom (ZX551ML) 128GB Specifications

The Asus ZenFone Zoom (ZX551ML) features a 5.5-inch HD IPS display with a resolution of 1920 x 1080 pixels and is powered by a 2.5GHz quad core processor and has 4GB of RAM. It comes with 128GB of inbuilt storage and has a 13.0-megapixel rear camera and 5.0-megapixel front camera. It comes with Android 5.0 Lollipop OS and support a 3000mAh battery capacity with 3G & 4G.


Form FactorBar
Screen TypeHD IPS Capacitive Touchscreen
Screen Size5.5 inches
Screen Resolution1920 x 1080
ProtectionCorning Gorilla Glass 4


ProcessorQuad Core
Speed2.3 GHz


Internal Memory128GB, 4GB RAM

Camera Features

Sensor Resolution13MP
Digital ZoomYes
Front facing camera5MP

General Features

OSAndroid 5.0 (Lollipop)
Bluetooth FeaturesV4.0+EDR
MessagingSMS, MMS, Email
USB ConnectorYes
Available ColoursBlack, White

Carrier Networks

2GGSM 850/900/1800/1900 MHz
3GWCDMA 2100 MHz




Dimensions78.84 x 11.95 x 158.9 mm


Media PlayerYes
Audio connector3.5mm



After Sales Service

Warranty Period1 Year


Warranty Period1 Year

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