IT Pro Verdict

Shoddy keyboard dock aside, this is a good Android tablet even if there isn’t quite enough to set the Z4 apart from its predecessors

Pros

+
Waterproof; Thin and light; Lengthy battery life

Cons

-
Screen brightness still lacking; Poor keyboard dock

Sony no longer makes Vaio laptops, having spun off the business as a separate Japan-only company, but you'd never know it from looking at the Japanese giant's latest Android tablet. The Xperia Z4 Tablet may look very similar to its predecessors, but it comes with a keyboard docking station so you can use it as a laptop. The docked tablet does look a lot like the ultra-portable Vaios of yesteryear.

Sony Xperia Z4 Tablet: keyboard

Although the keyboard is included with the Z4, it feels more like a hasty afterthought than a carefully designed and integral accessory. The docking mechanism relies on rubber friction pads rather than magnets or a plug-and-socket. As a result, you have to line up tablet and dock quite carefully to get a successful connection. Despite the physical contact, the keyboard relies on Bluetooth to work.

The hinge can't tilt back very far, only by approximately 100 degrees, so getting a comfortable viewing angle when using it on your lap can be tricky. Detaching the two without feeling you're about to break something isn't easy either. The docked tablet feels quite top-heavy too, which is especially noticeable if you're a heavy typist thundering keystrokes can cause the tablet to wobble distractingly.

All of this would be bearable if the keyboard was top-notch, but it isn't. Pairing the keyboard dock with the tablet was a fiddly and time-consuming process. Once docked, lag was often a problem with both typing and cursor movement lagging behind our finger strokes. Plus, since it uses Bluetooth, the keyboard requires charging. Yet there's no battery life indicator, either in software or on the keyboard itself, and the supplied USB charger only has a single port so you can charge either the tablet or the keyboard but not both simultaneously.

The keys are quite small too, especially the tab and cursor keys, but they do have enough feedback and travel. It's therefore faster and more comfortable to type on than the onscreen keyboard. There are some nice touches too, such as a full suite of Android-specific shortcut keys including one for accessing the Notifications drawer. This is especially handy given that using gestures can be very fiddly on the small, cramped and often quite laggy touchpad.

Sony Xperia Z4 Tablet: Android 5.0 Lollipop

One especially neat keyboard-related feature is that a Windows-style taskbar automatically appears on-screen whenever you connect the keyboard dock. It runs along the bottom of the screen and disappears when the keyboard is disconnected. As well as showing icons for your favourite apps, which you can customise, the taskbar also has a Start menu analogue listing your most recently used apps although oddly there's no keyboard shortcut for this menu.

On the left hand side of the screen is Sony's Start-style menu which appears with the taskbar whenever the keyboard dock is connected; to the right are Sony's calculator and web browser mini-apps

Unlike Samsung's Galaxy Tab tablets, the Z4 doesn't have the ability to run two apps onscreen simultaneously a feature that makes most sense when used with a keyboard and touchpad. The closest equivalent it has is a small number of simple mini-apps that float above regular apps in windows that you can resize and reposition. Mini-apps include a calculator, timer and a simple web browser that handily uses Chrome's URL auto-complete history.

Aside from these additions, Android 5.0 Lollipop is largely unchanged compared to the stock version of Google's operating system.

Sony Xperia Z4 Tablet: casing

At first glance, the Z4 appears little different from its predecessor the Z2. The plastic casing is available in black or white. Sony has avoided the current trend for narrow screen bezels, opting for wider ones instead. Although this looks a little old-fashioned, it makes it much easier to grip the tablet without inadvertently touching the screen and activating an onscreen control. This, combined with the weight of 389g which is light for a 10in tablet, make the Z4 easy to hold for long periods of time. The only hitch here is the 16:9 aspect ratio which is great for watching videos, but makes reading feel a little ungainly and unnatural.

The Sony Xperia Z4 Tablet is available in either black and white and with or without built-in 4G

As with the rest of Sony's Z-range of Android devices, the Z4 is waterproof. It survived submersion in a kitchen sink unscathed, so it'll easily withstand spilled drinks and rainfall. One change from other Z-series tablets and phones is that there's no longer a protective flap covering the micro USB 2 port, although flaps remain on the micro SD slot (and the SIM card slot on the more expensive 4G-equipped version). Although this means you will need to ensure the micro USB port is drained and dry before plugging anything in, the flap's absence does make the frequent ritual of plugging in a charging cable less fiddly.

Sony Xperia Z4 Tablet: battery life, performance and responsiveness

At least you won't need to recharge the battery too often. It lasted just over 16 hours when connected to 802.11n WiFi and browsing the web. It lasted 13 hours and 24 minutes while playing a H.264 video continuously.

The touchscreen was almost flawlessly responsive with only occasional lag. The Z4 is the first tablet we've seen with the eight-core 2GHz Qualcomm Snapdragon 810 processor the same processor used in many of this year's flagship Android phones. Paired with 3GB of memory, it performed very similarly to those phones and is one of the fastest tablets we've tested. The downside is that part of the casing became uncomfortably hot to the touch. Although other tablets can become warm to the touch when their processors are under heavy load, the heat was much more uncomfortable here. It did, at least, pass quickly.

Sony Xperia Z4 Tablet: screen and camera

Text looks very sharp on the Z4's 10in screen thanks to its high 2560x1440 pixel resolution. Contrast and colour accuracy were merely okay though with images slowing a slight blueish tint. In a marked improvement over previous Xperia tablets, the screen is dazzlingly bright at 100% brightness, but was much dimmer when turned down to 50% to save battery especially when compared to other tablets.

Sony makes the excellent camera sensors that go into the smartphones and tablets from many of its competitors, so it's a shame the camera here isn't quite up to scratch. Shots taken in dim lighting were either too blurry or too heavily smeared to be usable. Shots taken in bright daylight were far better, although modest magnification revealed smudged details while highlights tended to be blown out. It's good enough as a backup camera though.

Sony Xperia Z4 Tablet: conclusions

Although Sony's attempt to turn the Xperia Z4 Tablet into a hybrid via the included keyboard dock is largely a failure, the Z4 is still one of the best 10in Android tablets available. It still has a few flaws, but if you want an Android-based alternative to the iPad then this is the tablet to get.

If you do want a tablet with a keyboard, then you have plenty of alternatives to choose from although none are perfect. The iPad Pro 9.7 is surprisingly usable for a 10in tablet retrofitted into a hybrid, but the design choices of Apple's official keyboard screen cover won't suit everyone.

The Google Pixel C is almost perfect hardware-wise with its comfortable multi-angle keyboard and excellent key feel, but it's let down by the poor state of Android Marshmallow.

Android may be a great smartphone operating system, but its selection of tablet-optimised apps still tends to be rather shallow and it's poorly adapted for use with a hardware keyboard lacking some keyboard shortcuts and flexible multitasking features. At least the latter will become a standard feature in Android N, if the latest public betas are any indication.

This review was published on 01/7/2015 and has since been updated, most recently on 21/4/2016.