ASUS ZenFone Zoom review: The first smartphone with a real zoom lens

Overview

Mobile photography has become a major trend in recent years with phone makers working hard to constantly outdo one another with higher megapixel cameras, bigger sensors and wider aperture lens. For Taiwanese company ASUS, it's betting its chances on integrating optical zoom into a smartphone. To be clear, your current smartphone camera has a zoom function, but in actual fact it's using digital zoom, which works by cropping the image and enlarging it, compromising picture quality in the process. The ZenFone Zoom on the other hand has an actual optical zoom lens, the same kind you would find in a DSLR or compact digital camera. Zoom lens are far more complicated and bulkier than their fixed focal length counterparts, which is why we haven't seen one in a slim smartphone until now. Samsung was of course the first in the market with the Galaxy S4 Zoom and later the Galaxy K Zoom, but their form factor and handling was closer to a compact camera than a smartphone.

ASUS announced the ZenFone Zoom at CES 2015 alongside the popular ZenFone 2 and it was a long wait for this beast to arrive on our shores. Consumers in Taiwan were among the first to get the ZenFone Zoom last December before landing in Singapore last month.

With the competition pushing for bigger pixels and better lenses, is there a need for optical zoom in smartphones today? Let's find out in this review. But first, here's a quick overview of its specs:

Design & Handling 

As the ZenFone Zoom was announced along with the ZenFone 2, both smartphones sport the same design traits such as the concentric-circle detailing and aluminum frame. The aluminum frame has a smooth and premium finish. Like the LG G4, the ZenFone Zoom comes with a leather rear cover. However, the feel of the leather rear on the ZenFone Zoom is different from that of the G4 due to the treatment process. 

ASUS uses a burnished leather finish and traditional Italian leather tailoring where only 38% of the hide with the thinnest and toughest cut made the grade. It is noticeably rougher than the one on the G4 which isn't a bad thing as you get a better grip of the 5.5-inch phone. For some, it could perhaps be too rough that it might feel a bit like plastic; since this is subjective, you'll have to try it out personally. We also don't know how well the leather finish will fare against wear and tear, but the color choice (black) makes it less of a headache for maintenance.

The rear cover is removable via a slit at the bottom left corner. Hidden beneath the leather cover is a micro-SIM slot and a microSD memory card slot. You also can see the embedded 3,000mAh battery and the gigantic camera module. The latter reminds us of the Nokia Lumia 1020 which also has a huge camera bump. However, the camera bump on the ZenFone Zoom does not make the phone wobble when placed on its rear as there is another horizontal ridge at the bottom. As for the camera lens, it rests comfortably within the metallic disc. Therefore, you do not have to worry about scratching the lens. The heft of the camera lens is noticeable and makes the ZenFone Zoom feel a little top heavy. It also feels weird to come in contact with the metallic disc while handling a mostly leather-backed rear with your hand. 

The front of the ZenFone Zoom is dominated by a 5.5-inch IPS display with three capacitive navigation buttons at the bottom. Similar to the ZenFone 2 and ZenFone, there is no backlight for these buttons which can make navigation in the dark difficult. We sincerely hope ASUS takes some cues from Xiaomi which has addressed this issue with its affordable Redmi Note 3. 

Due to the width of the phone (78.84mm), right handed users may find it hard to reach for the Back button. In fact, the ZenFone Zoom is the wider than the ZenFone 2 (77.2mm) and Redmi Note 3 (76mm).

As a camera-centric phone, the ZenFone Zoom boasts "real camera buttons" on the bottom right, consisting of a dedicated shutter button and a shortcut button to start video recording immediately. You can press and hold either button when the screen is off to activate the camera. Both buttons are very well-designed and tactile. Just like a DSLR, the shutter button can be pressed halfway to lock the focus, exposure and white balance before pressing fully to take the shot. The top right section houses the power button and volume controls. In camera mode, the volume controls can be used for zooming.

Display

The ZenFone Zoom sports a 5.5-inch Full-HD (1,920 x 1,080 pixels) IPS display which is protected by Corning Gorilla Glass 4. The benefits of Gorilla Glass 4 include 2x more drop-damage resistance, 85% less likelihood of breakage and 2.5x more retained strength as compared to competitive glasses.

There is also an application of high-density fingerprint-resistant coating to minimize fingerprints and smudges. Another interesting feature of the display is the touch-distinction technology which ASUS claims to help the ZenFone Zoom register smoother swipes even if the display is damp. This should come in handy for users with sweaty palms/fingers. Like the ZenFone 2, the ZenFone Zoom also supports Glove Touch technology that bumps up the sensitivity of the display when you are wearing gloves. 

Similar to Night Shift on iOS 9.3, there is a blue light filter on the ZenFone Zoom. There is a slider for you to adjust the blue light filter from a less warm to a warmer tone. The function of the blue light filter is to make the screen less glaring when using at night and in doing so, it helps you sleep better. This feature can also be found on the ZenFone Selfie

ZenUI on Android 5.0 Lollipop 

The ZenFone Zoom runs on ZenUI, a customized Android overlay developed by ASUS similar to HTC's Sense and Samsung's TouchWiz. You can check out the core features of the ZenUI here: 5 notable features of the ASUS ZenUI. Over the past year, ASUS has added more than 1,000 new features to the ZenUI which include ZenMotion, ZenUI launcher, Themes and SnapView. Some of the features were discussed in our review of the ZenFone 2.

As ZenUI was unveiled in 2014, the interface looks a tad dated compared to the recent revamps we've  seen from the competition. It is also awkward to see the ZenUI still based on Android 5.0 Lollipop when Android 6.0 Marshmallow has been around for about 6 months. In a forum post, ASUS confirmed that the ZenFone Zoom is among one of the several devices to be updated to Android 6.0 in Q2 2016.

While ASUS is a bit slow in updating its mobile devices to the latest Android version, it is the exact opposite when it comes to issuing Android security patches. Android security patch is one of the various measures taken by Google to improve Android security and we found that the ZenFone Zoom is running on the latest patch dated 1^st April 2016. Considering how a study revealed 87% of all Android devices are still vulnerable to malware, this is a commendable effort by ASUS to at least protect its users.

Benchmark Performance

The ZenFone Zoom is powered by a 64-bit 2.5GHz Intel Atom Z3590 chipset (a speedier version of the Intel Moorefield that topped out at 2.3GHz when launched) and 4GB RAM. Overall, performance was smooth and we did not encounter any lag whatsoever. RAM usage by the OS was relatively heavy; slightly more than 2GB was available when we closed all apps in the background. Below are the benchmark scores, relative to the competition.

Quadrant

Quadrant evaluates a device's CPU, memory, I/O, and 3D graphics performance. The Atom Z3590 processor seems to lag behind the Atom Z3580 counterpart in the ZenFone 2 despite having the same amount of RAM. This makes absolutely no sense as the Intel Atom Z3590 was launched later than the Atom Z3580 and has a speedier core and GPU. ASUS might not have done a good implementation of this new processor.

3DMark Ice Storm Unlimited

Originally developed as a PC gaming benchmarking tool, 3DMark now supports multiple platforms including Android. The Ice Storm benchmark is designed for smartphones, mobile devices and ARM architecture computers.

For an in-depth understanding of 3DMark for Android, do head over to our article, "3DMark - Android Device GPU Performance Review." In a nutshell, it is an OpenGL ES 2.0 benchmark test that uses fixed off-screen rendering to run two graphics tests designed to stress the GPU performance of your device and a physics test to stress its CPU performance. The benchmark consists of three test portfolios: Standard (720p resolution rendering), Extreme (1080p resolution rendering with higher quality textures and post-processing effects), and Unlimited (disabled v-sync, display scaling and other OS factors that make it ideal for chipset comparison). 

Since all the recent flagship smartphones max out the scores for the Standard and Extreme tests, we will only be looking at the scores for Ice Storm Unlimited. The ZenFone Zoom fared almost as well as the ZenFone 2, which is once again unexpected because the Zenfone Zoom has a faster processor and GPU.

Sunspider Javascript

SunSpider JavaScript helps measure the browsing performance of a device when processing Javascript. It not only takes into consideration the underlying hardware performance, but also assesses how optimized a particular platform is at delivering a high-speed web browsing experience. The SunSpider benchmark further convinced us that software optimization may be at fault for the sub-par benchmark performance of the ZenFone Zoom.

Battery Life

Our standard battery test for mobile phones includes the following parameters:

• Looping a 800 x 480-pixel video with screen brightness and volume at 100%
• Wi-Fi and Bluetooth connectivity turned on
• Constant data streaming through email and Twitter

Equipped with a 3,000mAh battery, the ZenFone Zoom lasted 8 hours and 41 minutes which is quite decent compared to the competition. It managed to outlast the ZenFone 2 by more than an hour despite having the same display size, resolution and almost similar specs. Looking at the power consumption chart, you could see that the ZenFone Zoom has a lower power draw compared to the ZenFone 2.

Portability

We measure the portability of a device by calculating its battery life to (weight x volume) ratio. As the ZenFone Zoom is the second heaviest and has one of the biggest footprints, it did not fare well in the Portability Index.

Camera Performance

On paper, the ZenFone Zoom boasts one of the most impressive suite of imaging hardware. Dubbed the "new era of mobile photography", the ZenFone Zoom's rear camera has a 13-megapixel, f/2.7-4.8, 28-84mm (35mm equivalent) 10-element lens created by Japanese optics firm Hoya. Hoya is known for its expertise in color filter glass and aspherical lens, which may explain its role in helping ASUS achieve 3x optical zoom in the ZenFone Zoom.

As highlighted in our local launch news, to keep the phone relatively thin - it's 11.95mm including the camera bump, but tapers down to 5mm at the sides - ASUS has worked with Hoya to develop a dual-prism periscope module design using 6.2mm D-cut lenses. This not only maximizes incoming light but also means that the bulk of the lens can be fitted length ways down the phone's body, instead of across. This means when you zoom in and out, you'll not see the lens racking in/out and it's all managed within the body of the phone, which is fairly impressive and thus helping create the world's slimmest 3x optical zoom equipped smartphone. What we're not so sure about is the variable aperature lens, which could affect its optical zoom performance despite ASUS mentioning the design maximizes incoming light.

The ZenFone Zoom also boasts optical image stabilization, a highly sought after feature that is standard in most flagship smartphones today. Other notable specs include 0.03s ultra-fast laser autofocus, a dual-LED real tone flash, and macro focusing as near as 5cm, Super Resolution mode (combining four 13-megapixel photos to create a single 52-megapixel image) and ASUS's coveted PixelMaster technology. You can find out more about PixelMaster in our dedicated article here. 

The front-facing camera has a 5-megapixel sensor with wide-angle lens, PixelMaster and a Selfie Panorama mode capable of taking up to 140 degrees wide shots. If there is one thing lacking on the ZenFone Zoom, it will be 4K video recording. The ZenFone Zoom only supports three video resolutions: Full-HD (1,920 x 1,080), HD (1,280 x 720) and TV (640 x 480). Moving on, let's take a look at how the camera interface looks like on the ZenFone Zoom:

Image Quality and Experience

Do these impressive specs translate into great performance? Well, check out the photos below:

Unfortunately, the image quality delivered by the ZenFone Zoom is average compared to other 13-megapixel shooters we've seen. If you zoom in to some images above (click on the individual image to zoom), you will notice some artifacts. We reckon the issue lies with the image processing and the quality of lens used.

To activate optical zoom, simply press the volume controls and a slider will appear on the right to guide you. It feels comfortable and natural as though you are using a point-and-shoot camera, and is nowhere as clumsy as the Samsung Galaxy K Zoom. 

While we appreciated the 3x optical zoom and fast autofocus, image quality leaves something to be desired. Ultimately, the ZenFone Zoom doesn't fit in the class of the Samsung Galaxy S7, LG G5 and the Apple iPhone 6s Plus. Optical zoom is a "nice-to-have" feature, but great image quality is something that consumers expect from a camera-centric phone.

Conclusion

The ZenFone Zoom is available in two models; the first one comes with 64GB internal storage space at S$659 while the second model has double the storage to 128GB at S$729. 

ASUS did a decent job with the ZenFone Zoom, but it failed to live up to its marketing claim of a great camera phone. While other phone makers compete with better lenses, bigger pixels and smoother image processing, ASUS took a different path by focusing on optical zoom capability. But having optical zoom without delivering the best image quality makes the ZenFone Zoom look like a half-baked product. This strategy may not bode well now, but should the industry move towards adding optical zoom capability in smartphones, ASUS can learn from this experience and come up with something better.

Unless you absolutely need optical zoom in your next phone, there are better alternatives on both ends of the price range. Given more budget, the Samsung Galaxy S7 and LG G5 / V10 are worthy of your consideration. On the other end, the one-year-old Galaxy S6 at current street price is still a very compelling choice with its superior camera performance.

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