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Asus ZenFone 3 Zoom

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  • Pros

    Affordable. Dual-camera optical zoom. High-resolution audio. Lots of unique features and customization options. Good build quality. Stellar battery life. Super-bright display.

  • Cons

    Dated software with heavy UI layer. Low-light camera performance could be better.

  • Bottom Line

    The Asus ZenFone 3 Zoom stands out from the crowd of unlocked phones thanks to stellar battery life, dual-camera optical zoom, and a slew of unique features, but a lackluster software experience limits its appeal.

By Ajay Kumar

Better battery life is a spec most manufacturers ignore in the quest for thinner, lighter phones, but Asus is listening. The unlocked ZenFone 3 Zoom ($329) packs a massive 5,000mAh cell into an attractive metal body, for some of the best battery life we've tested. You also get solid performance, dual cameras with 2.3X optical zoom, and a host of unique features and customization options. It's an attractive option for the price, particularly if you're focused on battery life, but Motorola's Moto G5 Plus remains our Editors' Choice award for its superior software experience and compatibility with all major US carriers.

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Design, Display, and Features

The Zoom is proof that phones with big batteries needn't be bricks. Measuring 6.1 by 3.0 by 0.3 inches (HWD) and 6.0 ounces, the Zoom is slightly smaller than the iPhone 7 Plus (6.2 by 3.1 by 0.3 inches, 6.6 ounces) and just a bit bigger than the Moto G5 Plus (5.9 by 2.9 by 0.3 inches, 5.5 ounces). That's a pretty impressive feat, considering the Zoom's battery is nearly twice as big as the ones in either of those devices.

Zoom back

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The phone has a sleek metal body available in black (pictured here), gold, and silver. The right side has a volume rocker and power button. The bottom features a 3.5mm headphone jack, a USB-C charging port, and a speaker. The left side has a SIM/microSD card slot and worked fine with a 256GB card. You can also use two SIM cards instead, but only one will connect to a 4G network.

On the back you'll find the dual-camera setup with a laser autofocus sensor and dual-LED flash. A square fingerprint sensor below can be enabled for functions like tapping twice to quick launch the camera app, acting as the shutter key, and answering phone calls.

The Zoom has a 5.5-inch, 1,920-by-1,080 AMOLED display clad in Gorilla Glass 5. The resolution works out to a crisp 401 pixels per inch, matching the G5 Plus. The panel is rich and saturated out of the box, though you also have the ability to tweak color temperatures to your preference. The AMOLED panel not only provides inky blacks, but saves power by lighting pixels only as needed. Viewing angles are great, and using the phone outdoors is no problem, as it reaches up to 500 nits of brightness at maximum.

Network Performance, Connectivity, and Audio

The Zoom is available unlocked and supports GSM (850, 1800, 1900MHz), WCDMA (1/2/4/5/8), and LTE bands (1/2/3/4/5/7/8/17/28). That means you can only use it on GSM carriers like AT&T and T-Mobile, and you'll likely get better connectivity on the former, since the phone is missing band 12, which provides better coverage and improved indoor reception on T-Mobile. That said, the phone performed fine throughout our testing in midtown Manhattan, showing a top download speed of 11.4Mbps on T-Mobile's network.

Other connectivity protocols include Wi-Fi on the 2.4GHz band and Bluetooth 4.2. There's no NFC, which isn't unusual for this price range.

Zoom display

Call quality is solid. Transmissions are clearly audible and have little to no garbling, though voices can sound a bit robotic. Noise cancellation is good at blotting out background noise, and with the loud earpiece volume, you shouldn't have trouble carrying on a conversation in a noisy environment. VoLTE is supported, Wi-Fi calling isn't.

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Audio quality is also solid. Similar to the ZTE Axon 7, the Zoom supports high-resolution 24-bit audio playback through the headphone jack. Using a feature called Audio Wizard you can adjust music using the built-in equalizer and use DTS Headphone:X virtual surround sound for movies, music, and games. Listening with a pair of high-fidelity Auros earphones, I was able to notice a significant improvement in clarity and sound quality compared with phones that don't have the same enhancements. Bass-heavy metal came through particularly well, with more clearly defined lyrics, less distortion, and a warmer sound. Virtual surround sound is subpar at best, however, actually worsening audio quality by narrowing the sound field.

The bottom-firing mono speaker has an NXP Smart Amp. Aside from getting quite loud, I couldn't detect a difference between it and other downward-facing speakers. It's no match for the thunderous front-facing speakers on the Axon 7.

Processor and Battery

The Zoom is powered by a Qualcomm Snapdragon 625 processor clocked at 2.0GHz. It's a capable midrange chipset, scoring 62,504 on the AnTuTu benchmark, which measures overall system performance. That's similar to the G5 Plus (63,845), which has the same processor, and higher than the Kirin 655-powered Honor 6X (56,602). The Axon 7 (141,989) has a much more powerful Snapdragon 820 processor, but it's also more expensive.

In terms of real-world performance, the ZenFone 3 Zoom is smooth. Its 3GB of RAM is enough that multitasking isn't a problem, and I never encountered any lag or stuttering. The phone also had no trouble handling high-end games like GTA: San Andreas.

Asus has packed the Zoom to the brim with software enhancements to improve performance. The most notable is Power & Boost, accessible through the notification shade. It's a memory manager that cleans up background apps when the screen is off, and can stop apps from automatically starting when you turn the phone on.

The Zoom also has phenomenal battery life. It clocked 10 hours, 30 minutes in our rundown test, in which we stream full-screen video over LTE at maximum brightness. That outclasses all its competitors including the G5 Plus (7 hours, 35 minutes), the Axon 7 (6 hours), and the Honor 6X (5 hours, 35 minutes). The only phone that comes close is the OnePlus 3T, at 10 hours. With average use, you can easily go two to three days without having to recharge. If there's one downside to the massive battery, it's that even with fast charging it'll still take a few hours to charge the Zoom.

Zoom camera


Dual-camera phones are becoming increasingly more common, offering features like wide-angle shots in the case of the LG G6, bokeh on the Honor 6X, and telephoto zoom on the iPhone 7 Plus. With the Zoom you get a pair of rear-facing f/1.7 12-megapixel shooters capable of 2.3x optical zoom, slightly higher than the 2x zoom on the 7 Plus. It also has a laser autofocus sensor, a dual-LED flash, and Dual Pixel Phase Detection Autofocus.

In good light the phone takes crisp, detailed shots. Autofocus locks on quickly and noise is fairly minimal. Color reproduction is accurate, though perhaps a little dull if you prefer more saturated colors. In the camera app you'll find a number of modes and settings, including bokeh (which blurs backgrounds to make objects stand out in the foreground), but the most notable is the 2.3x optical zoom, which allows you to get in close on an object without the loss of detail that comes with digital zoom. It works well, as you can see in the images below, though overall quality isn't up to par with the iPhone 7 Plus—some of the pictures I shot on a cloudy day were a bit muddy.

Zoom 1

Zoom 2

Zoom 3

Zoom 4

Despite claims from Asus that the phone has 2.5 times the light sensitivity of the iPhone 7 Plus, it wasn't apparent in testing. The rear sensors took soft, noisy shots indoors, with overall subpar quality compared with flagships like the Google Pixel XL. That said, you can tweak ISO and shutter speed for better performance.

The Zoom is capable of recording 4k video at 30fps, and 1080p at 60fps. There's no optical image stabilization, but the electronic image stabilization works fairly well and video quality is good. However, in a few instances, the camera app refused to record in 4k, generating an error message. The problem didn't crop up when attempting to record 1080p30.

Zoom bokeh

The 13-megapixel front-facing camera is excellent. Pictures are crisp, autoexposure has no issue adjusting to different lighting conditions, and backgrounds look clear. There's a built-in Skin Brightening slider enabled by default that can make your facial features look soft, but it's easy to turn off if you don't want to look like an airbrushed supermodel.


The ZenFone 3 Zoom comes running Android 6.0.1 Marshmallow with Asus' custom ZenUI 3.0 skin on top. Simply put, the software is outdated, and the custom skin makes significant changes to stock Android. In addition to visual elements like an altered lock screen, notification shade, and settings menu, the phone is packed with features that range from useful to unusual.

The one we like the most is the home screen manager that appears when you swipe up from the app drawer. It allows you to edit every aspect of the phone's appearance including icon size, alignment, scroll effects, and font size. You can also download new themes, third-party icon packs, and change animation speed. Other useful settings include a call recorder baked into the Dialer app, Gloves mode to increase screen sensitivity, an Outdoor mode to increase earpiece volume, Kids mode to restrict access to certain apps, and Easy mode to launch a simplified UI. It's a nice degree of customization, but it also results in a profusion of toggles, modes, and menus, which can make the phone a bit bewildering to use.

Zoom home

Since the Zoom is unlocked, you're spared from carrier bloatware, but Asus makes up for it with its own apps. There are 11 preinstalled, non-removable apps that offer additional functions like note-taking, quick memos, and game recording. You're left with 20.5GB out of 32GB available storage. You can always add a microSD card if you need more.


The $329 ZenFone 3 Zoom sits between the $299 Moto G5 Plus and $399 ZTE Axon 7 in terms of price. With its gargantuan battery, dual-camera setup with telephoto zoom, and host of unique features, it manages to stand out, which is more than you can say about many phones in the price range. But it's 2017 and Android O is around the corner, so we can't overlook the fact that the Zoom comes running two-year-old software. That's why the G5 Plus remains our Editors' Choice on the more affordable end: It features similar hardware, along with newer software and a greater likelihood of updates, no to mention compatibility with every major US carrier. For $100 more, ZTE's Axon 7 is nearly a year old, but it just received a Nougat update with Daydream support, putting it nearly on par with current flagship phones for nearly half the price.

Ajay Kumar By Ajay Kumar Mobile Analyst

Ajay Kumar is PCMag's Analyst obsessed with all things mobile. Ajay reviews phones, tablets, accessories, and just about any other gadget that can be carried around with you. In his spare time he games on the rig he built himself, collects Nintendo amiibos, and tries his hand at publishing a novel. Follow Ajay on Twitter @Ajay_H_Kumar. More »

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