Asus has been delivering exceptionally well time and again with its Zenfone series of devices. So much so that they literally have Zenfone fanboys in India today. What the Zenfone series does differently as compared to other brands is that it launches a plethora of variants for the same device. This helps in catering to various different class of consumers. There is a huge difference in specs and performance when it comes to Zenfone 3 variants. The one that we have is the most inexpensive Zenfone 3 variant and according to me, the most suited for Indian market considering the price point. Another thing to note is that Asus has finally ditched Intel and gone with Snapdragon SoC. So lets get on with the Asus Zenfone 3 Review.

zenfone-3-14Asus Zenfone 3 ZE520KL Specifications

  • 5.2-inch (1920 x 1080 pixels) Full HD Super IPS+ display  2.5D Corning Gorilla Glass 3 protection
  • 2GHz Octa-Core Snapdragon 625 14nm processor with Adreno 506 GPU
  • 3GB RAM with 32GB storage, expandable memory with microSD
  • Android 6.0 (Marshmallow) with Zen UI 3.0
  • Hybrid Dual SIM (micro+nano/microSD)
  • 16MP rear camera with dual-tone LED Flash, PDAF, Laser AF, f/2.0 aperture, 6P Largan lens, 4 Stop OIS
  • 8MP front-facing camera, f/2.0 aperture, 88-degree wide-angle lens
  • Fingerprint sensor
  • Dimensions: 152.59 x 77.38 x 7.69mm; Weight:155g
  • 4G LTE with VoLTE, WiFi 802.11ac (2.4 and 5GHz) MU-MIMO, Bluetooth 4.2, GPS, USB Type-C
  • 2650mAh battery

Design, Build Quality and Display – Asus Zenfone 3 Review

Most of the earlier Zenfone devices were made out of a mix of many materials such as plastic, leather, metal or all three. With most of the tech giants going with the monotonous metal Unibody design, Asus has again shown its different (and much needed) approach to innovation by molding the Zenfone 3 in a body composed of metal and glass. Even the cheapest variant priced at Rs 22,999 will make you feel like you are holding an uber premium phone like the Samsung S7. The glass and metal body is a sight to look at and by no means does it mean that the build quality has gone down. Instead, the Zenfone 3 is sturdier than any previous generations Zenfones. Asus has provided 2.5D glass on both sides of phone, which gives the phone a fabulous look as well as protection. It has a chamfered chassis made of high-grade metal which helps in enhancing that premium feeling. Also worth noting is the fact that glass on both its sides is also Gorilla Glass 3, so be assured.

zenfone-3-10The rear of the device is just fantastic to look at. Asus has added a hairline spun metal concentric circle pattern which looks even more beautiful as light bounces off it. According to Asus, this is a reminiscent of the water ripples of a pond, indicating the focus on the “Zen” elements. This quite truly is a unique design feature seen only in Asus devices.

zenfone-3-4The Frame of the device is well built and rigid. It is made out of aluminum alloy and has finely sandblasted surface finish with the 2.5D glass edges blending in with the curve of the frame.

Zenfone 3 features a 5.2-inch 1080p display with a Screen to body ratio of 77.3 %. This is quite a welcome move. Most of the Devices these days sport a 5.5 inch screen and thus the overall size increases considerably. They thus become quite difficult to hold and use with one hand for the average Indian hand size. I quite enjoyed using the Zenfone 3 as compared to my other devices which feature a larger screen. The display on the Zenfone 3 is a Super IPS+ panel. The display is extremely bright too as compared to most phones in the market. At 600 nits, the bright display is very clear under direct sunlight and a pleasure to use.

zenfone-3-2Above the screen of the Zenfone 3, is a 8MP front facing camera along with the proximity sensor and a hidden LED notification light. The area beneath the screen features touch capacitive buttons just like the earlier Zenfones and sadly just like the previous versions, these too are not backlit. This is not a problem as you get used to the device in no time but it was a bit tiring for the initial days to use the Zenfone 3 in the dark sans the backlit buttons.

zenfone-3-5The right side of the device has the metallic volume rocker and the power buttons which give a good haptic feedback. The buttons are sturdy unlike some of the Motorola phones where you feel the buttons might just fall off.

zenfone-3-8Left side of the device contains a hybrid sim card tray. This means that you can either use 2 SIM cards or 1 SIM + 1 microSD card. Though I felt the 32GB on the device was quite decent for regular music, pictures, videos and apps.

zenfone-3-6The bottom of the Zenfone 3 has a USB C port for charging and data syncing. We tried using the LeEco Type C earphones but did not get audio output out of the Type C port. It is notable that this is the first Zenfone to come with USB TYPE C PORT. Next to the port is the speaker grill and the microphone hole.

zenfone-3-7The top side of the Zenfone 3 has a tiny microphone hole for noise cancellation and 3.5mm headphone jack. Yeah, Jack survives.

A problem I faced with the Zenfone 3 was that the Glass back is a total fingerprint magnet! It is susceptible to smudges and greasy prints from your hands. This however is just a cosmetic problem and since most Indians use their smartphones with cases and covers, this should not be a big problem as such.

zenfone-3-12The rear side of the Zenfone 3 also contains a 16 MP camera. The camera sits on the top of the phone and is covered with Sapphire glass. Alongside the camera, there are LED flash and the laser autofocus and just underneath it is the Fingerprint sensor.

The fingerprint scanner beneath the camera module on the Zenfone 3 is one of the fastest I have ever used. I will go as far as to say that perhaps the Zenfone 3 has the fastest fingerprint scanner on a phone that I have used. It was easy to set up and simple to use. It worked correctly 19/20 times for me.

Software – Asus Zenfone 3 Review

The device comes with Android 6.0 Marshmallow out of the box. That is a welcome move from Asus. Asus’s highly popular ZenUI is running on top of Andoid 6 and is quite fun to use.

zenfone-3-13This is hugely customizable and allows for you to customize the device as per your need. I have said this before and I will repeat it now, ZenUI is one of the best custom UIs to run on your android devices. Some its added features such as Touch gestures and Asus Mobile Manager makes using the device easy for most people. The device however, just like most other Asus devices, comes with a lot of bloatware but thankfully most of these apps can be disabled/uninstalled.

zf3-zmYou can ofcourse download icon packs, skins and tonnes of other customizable content from Asus’s store for free to change how the software side of your Zenfone 3 looks like.

Performance – Asus Zenfone 3 Review

The Asus Zenfone 3 ZE520KL is packed with a Snapdragon 625 Octa-core processor running at 2 GHz along with Adreno 506 GPU. Asus has taken quite a balanced approach with the processor this time. Instead of following the rat race of integrating Snapdragon 820 they went with more energy efficient Snapdragon 625 which then consumes lesser battery. It also heats much lesser than the SD 820.

zenfone-3-3The Zenfone 3 base model which I have comes with 3 GB of RAM and this is quite good for everyday use. I feel anything over 4GB RAM is quite an overkill especially if one is not into gaming. The phone felt quick and responsive for most parts and with a dozen apps running in the background, it did not get any slower. The device also does not heat up like other devices which playing heavy games like Asphalt 8. All in all I was very happy with the experience I got out of the Zenfone 3 as far as performance is concerned.

Camera – Asus Zenfone 3 Review

Asus was quick to publicize the Zenfone 3 as “Built for Photography” thus making sure that the camera of the Zenfone 3 does not go amiss. The camera quality of the previous Zenfones has been average at best compared some of the other devices in the market. This, however is not the case with the Zenfone 3. The camera on the Zenfone 3 ZE520KL is equipped with 16 MP Sony Exmor RS IMX298 sensor with 6 elements Largan Lens along with Sapphire glass cover. The Pixel size is at 1.12 um and the sensor size comes in at 1/2.8″.

zenfone-3-11The camera on the Zenfone 3 has a maximum aperture of f2.0 and comes with both OIS for Photos and ESI for Video. This is not it, Asus has not forgotten to include their popular LASER AF system in the Zenfone 3. This allows the phone to focus at lightening speed, technically the response time was 0.03 sec and not just this, the Zenfone 3 has both Phase detection as well as Contrast Detection for autofocus. If Asus lets me keep the device for a tad longer, I might even come out with a separate camera review of the Zenfone 3. Personally, I was very impressed with the Zenfone 3 camera.

The Camera module at the back is assisted with a dual tone LED flash and a color correction sensor. This is phenomenal considering that the Zenfone 3 manages to capture life like colors spot on.

For shooting still images sans any shake, the camera has 4-axis OIS (Optical Image Stabilization)and for shooting videos, it has 3-axis EIS (Electronic Image Stabilization) and it can record videos in 4K UHD resolution. Asus lets me click 32 sec long exposure images in manual mode or even 140-degree selfie panorama by front camera.

Primary Camera Front Camera
16MP Camera, f/2.0 aperture, 6 P Largan lens 8MP Camera , f/2.0 aperture
PixelMaster Camera Modes:

  • Back Light (HDR) Mode
  • Low Light Mode
  • Manual Mode (for DSLR-like camera detail settings)
  • Real Time Beautification Mode
  • Super Resolution Mode (for up to 4X resolution photos)
  • Night Mode
  • Depth of Field Mode
  • Photo Effect Mode
  • Selfie Panorama
  • GIF Animation Mode
  • Panorama Selfie Mode
  • Miniature Mode
  • Time Rewind Mode
  • Smart Remove Mode
  • All Smiles Mode
  • Slow Motion Mode
  • Time Lapse Mode
PixelMaster Camera Modes:

  • Back Light (HDR) Mode
  • Low Light Mode
  • Real Time Beautification Mode
  • GIF Animation Mode
  • Panorama Selfie Mode

Deep Trench Isolation (DTI)


The ZenFone 3’s sensor features a technology called Deep Trench Isolation or “DTI”. DTI produces clearer and finer photo details by preventing light hitting the surface of a pixel on the sensor from leaking to its neighboring ones through its transparent structure below. DTI does this by using embedding the rows and columns of pixels in microscopic trenches with walls that separate them. These trench walls prevent photons of light from leaking from one to another and isolate the light hitting the surface of the pixel to that pixel only – hence the technology’s name.

Color Correction Sensor


Photos shot in overly strong warm (yellowish) or cool (bluish), or mixed lighting environments often appear with inaccurate colors. The ZenFone 3’s color correction sensor resolves this by first detecting the lighting in the scene and automatically adjusting the resulting colors in the photo to look natural and accurate.

0.03 Second “TriTech” Autofocus

zf3-ttfThe ZenFone 3 is also among the very few phones to offer a triple technology autofocus system that combines 1) an advanced second generation laser, with 2) phase detection and 3) conventional contrast detection for continuous focus, which achieves extremely rapid 0.03-second autofocus in any environment. The advanced system is also able to reach continuous autofocus on moving subjects.

4-axis Photo OIS


The handheld shooting of photos with slow shutter speeds in environments that need them often results in blurring. The ZenFone 3’s optical image stabilization (OIS) system detects hand movements along four axes – 1) up and down shifting (Y-axis), 2) left to right shifting (X-axis), 3) pitch (up-down pivoting), and 4) yaw (left-right pivoting) – and instantaneously moves the sensor in the exact magnitude and direction of the movements detected. This OIS system enables the photographer to use shutter speeds that are up to four stops slower, and can mean the difference between blur or sharp photos shot with slow shutter speeds.

3-axis Video EIS

zf3-eisHandheld videos shot with the ZenFone 3 are kept steady during recording using its electronic image stabilization (EIS) system. The system senses movements along three axes –

  1. Pitch (up-down pivoting)
  2. Yaw (left-right pivoting)
  3. Roll – and automatically corrects them with its powerful imaging processor by comparing frames and removing the shaking motion.

    4K Video Recording

    The EIS video output of the ZenFone 3 has a maximum resolution of 4K (3840 × 2160). Made possible by the phone’s high-resolution sensor, 4K videos offer the incredible detail that is a whopping four times that of Full HD (1920 x 1080) and also matches the resolution of the highest resolution TVs currently in the market.

    HDR Pro and Real Time HDR

    zf3-hdrIn HDR Pro mode, the camera can analyze photos and create the perfect exposure by intelligently lowering the brightness in overexposed sections, and increasing the brightness by up tp 400% in underexposed parts. The result is a photo with greater detail and well-exposed sections throughout. This mode is good for taking photos with extremely contrasting lighting – like shooting a subject in the shadows against a bright background. Unlike the HDR modes of other smartphones, the ZenFone 3’s HDR photo results are shown in real time on the display when framing the shot – so what you see is what you get as the resulting photo.

Low Light Mode – In low light conditions, the ZenFone 3’s Low Light Mode can combine four adjacent pixels on
its sensor to work as a single large pixel that has far greater light sensitivity. This mode increases the light
sensitivity of the sensor by up to 400%, allowing photos to be shot in low light conditions at faster shutter
speeds that prevent blurring, and/or without the harsh, overpowering light of a flash. Although using this
mode causes the photo resolution to be reduced to a quarter of the original sensor’s resolution, it is better to
be able to shoot in dark environments than not at all, and the ZenFone 3’s high resolution is still able to
produce a decent 4 megapixel photo in this mode. This low light mode, combined with the OIS of the ZenFone
3, allows it to shoot clearer photos in dim conditions compared to other smartphones.zf3-llm

Professional manual creative controls – A scene can be interpreted in many ways, and the phones’ auto or
preset modes may not always render the photo you want. For this, the ZenFone 3 offers users a set of manual
controls. These professional creative settings include custom white balance, Exposure Value (EV), ISO sensitivity,
shutter speed and focus, making the ZenFone 3 a powerful tool for learning the fundamental skills of
photography, and allowing users to creatively shoot scenes in many different interpretations.


32 second slow shutter mode – The most impressive of the ZenFone 3’s manual creative controls is the slow
shutter mode that allows photos to be shot with up to 32 seconds of exposure time. Typically used for low light
or night photos, this mode is ideal for shooting night landscapes, capturing the light streaks of passing traffic or
capturing stationary subjects in very low light conditions without the harsh lighting of a flash. This mode needs
the phone to be shot from a stable, non-moving platform, and is best used with a self-timer so that the
pressing of the shutter button doesn’t cause shaking that will blur the resulting photo.


And there are many many many more modes to play around with depending on the situation in front of the photographer. Truly, built for photography.

Camera Samples: Asus Zenfone 3 Review

Low Light mode gives sharp non-grainy results
Low Light mode gives sharp non-grainy results
Macro mode is quick and lets background go in a comfortable blur
Macro mode is quick and lets background go in a comfortable blur


Super resolution mode allows for a great color range and sharpness in overall picture
Super resolution mode allows for a great color range and sharpness in overall picture
Low light shots inculcate a great color rendition
Low light shots inculcate a great color rendition
Manual mode allows one to click such long exposure light trails
Manual mode allows one to click such long exposure light trails
Asus allows us to click a long exposure shot upto 30s which is DSLR standard for bulb mode
Asus allows us to click a long exposure shot upto 30s which is DSLR standard for bulb mode
And that’s a happy Zenny!
Long shutter speeds can also lead to light painting such as this
Long shutter speeds can also lead to light painting such as this

p_20161017_005852_vhdr_auto-2Battery Backup : Asus Zenfone 3 Review

The inexpensive Zenfone 3 carried a 2650mAh battery, which at first sounds nothing worth boasting about. BUT, it is everything worth boasting about! This is one of my most favourite features of the Zenfone 3. The battery optimizations have been perfected well enough on the Zenfone 3 for the battery to last you a whole day (atleast) on 4G + WiFi. While using the device as my daily driver I played games, watched a couple of videos, clicked ramdon pictures and listened to music. All this and the battery lasted a whole day with some juice still left. While using the Zenfone 3 as my secondary phone, well, it lasted for 2 days and had around 15% battery left. I still use my secondary phone quite a lot and hence I have to say, Kudos Asus! Till now, I had praised Apple to be able to utilise a sub 3000mAh battery to provide a whole day’s worth of juice, now, Asus has joined the party too.

Pros and Cons:

Based on my usage of the device for a couple of weeks, I have listed some of the advantages and disadvantages of the device.


Beautiful, Fashionable Design

Super IPS+ Display

Good Performance

Amazing Camera


Tad bit overpriced compared to competition

Fingerprint magnet

Can be slippery

Final Verdict : Asus Zenfone 3 Review 

zenfone-3-1Asus has worked tremendously hard in integrating the best of all worlds in the Zenfone 3 and to a great extent they have succeeded. The camera is brilliant and if you are into smartphone photography, you’d be more than happy to experiment with the plethora of modes. The battery optimization is on point with the battery being very efficient. The processor is quick and snappy enough to be able to play games and multitask with a dozen or more apps. Overall, for the price point, if you want a phone which is a beast but looks like a beauty, go for the Zenfone 3!

Build Quality
Battery Life
Value for Money
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When not geeking over tech related stuff, found trekking in the mountains with his trusted Canon by his side.