Finding a compact phone with flagship specs is something of a rarity these days, with many manufacturers delivering smaller-screen devices in the mid-range instead. Not so the Sony Xperia Z3 Compact, a device powerful enough to stand up to its larger-screen rivals.

Unlike most other Android smartphones with screens typically 5-inches or larger, the Z3 Compact fits neatly into hand and pocket thanks to its 4.6-inch panel. That will make this portable powerhouse desirable for many seeking something smaller. But is it worth your cash?

Sony has been refreshing and releasing phones with unparalleled frequency. The Xperia Z OmniBalance design of the Z3 Compact is the latest evolution, a squat and almost muscular looking phone that avoids the vast expanse of its Z3 big brother.

The Z3 Compact measures 127 x 64.9 x 8.6mm and weighs 129g, with tempered glass both front and rear. The frame holding these glass panels together Sony calls "liquid reflection" - it's plastic with nylon corners to try and reduce damage should you drop it - that offers a sort-of frosted appearance.

Sony Xperia Z3 Compact review

It feels like a well-built phone in the hand and is easy to handle with plenty of grip thanks to that compact size. No phablet scale monster that can so easily slip from the hand to be found here. But if we have one criticism it's that the frame, with its nylon corners and all, isn't as seamlessly integrated as we'd like and dust gathers in the small trough around the display.

As the Z3 Compact is also waterproof - another bonus, offering an IP65/68 rating for full submerging to 1.5m - the ports are covered except for the proofed headphones socket. There are two flaps on the left-hand side, one accommodating the microSD card slot and the Micro-USB, the other housing the nano SIM.

You'll need these flaps sealed tight to keep the water out, and as the charging port is under one you'll need to make sure it's closed tight after each charge. Although you're probably not going to buy this phone just for underwater photography, the added reassurance of that a spilled pint, drop in the toilet or when playing Dumb Ways to Die in the bath isn't going to do any damage.

Sony Xperia Z3 Compact review

To avoid opening that flap for charging, and as with other Xperia Z devices, there's also the option to buy a charging dock - the DK48, priced £30 - that is well worth it as a convenient bedside charger.

It might be small in size, but there's no denying that the Z3 Compact delivers a whole lot of phone for the money. And with a £429 SIM-free price (direct from Sony) it's positioned very aggressively.

The Xperia Z3 Compact has a 4.6-inch display, with a 1280 x 720 pixel resolution. The display makes great use of the available footprint, without excessive bezel to any side. There's some space top and bottom, which houses the front-facing speakers, but we like how Sony has struck a happy balance here - it doesn't look too out of proportion, which is something we've said of previous Z devices.

Sony Xperia Z3 Compact review

The resolution means a 319ppi pixel density, putting it in the same sort of territory as the iPhone 6 or the Samsung Galaxy Alpha. Smartphone fans will know that this isn't the highest resolution around at this size - the 4.7-inch HTC One M7 had a 1920 x 1080 resolution, for example - but at 4.6-inches the Sony gives a good showing for itself.

The display is somewhat prone to fingerprints, but look beyond those and you'll see ample details and lots of punch to colours. It's an IPS LCD display which is important for wide viewing angles, while Sony's Triluminos and Live Colour LED labels and X-Reality Engine are the processing means to those vivid colours.

As we've said before now, sometimes those enhancements can push things a little too far, but there's always the option to switch them off. There's the option for super-vivid colour boost, for example, but we'd advise against that as it tends to boost to the detriment of detail. X-Reality does a good job and we'd say stick to that for phone use, as it adds saturation and contrast to images. Below is a comparison of the three settings on the same image.

Sony Xperia Z3 Compact review

Sony says the Z3 Compact has the brightest display it's ever used in a smartphone and we've had no problems viewing it in bright conditions, apart from those irksome fingerprints. It's also possible to adjust the screen's white balance, although the option to make your display have a red, green or blue hue really isn't of that much use. By default the whites are white enough and the blacks are pretty good too.

However, in some situations the viewing angles can be a problem, such as when wearing polarised sunglasses. Turn the display into landscape mode and it's entirely invisible in that orientation when wearing such glasses. Not that we wear sunglasses all the time but, you know, it's still a potential annoyance.

Overall, at this size the Z3 Compact's display is decent, despite not being a resolution jump over its predecessor. We like the colour and available detail, as well as the options for boosting and tweaking, but suspect in the resolution race that the next Compact model will gain a bump in resolution.

Under the hood is a 2.5Ghz quad-core Qualcomm Snapdragon 801 chipset, backed by 2GB of RAM, making the Sony Xperia Z3 Compact a powerhouse for its size. 

As was the case with the Sony Xperia Z1 Compact, there are few devices that offer this sort of power. The Samsung Galaxy Alpha is a respectable rival, but is over £100 more expensive, while the Galaxy S5 Mini, like the HTC One mini 2, is a lower spec altogether.

Sony Xperia Z3 Compact review

The result is that this compact device responds with the deftness of flagship phones. Apps are fast to open, so those power hungry games will happily load quickly for your entertainment.

It's not without some compromise however: work the Xperia Z3 Compact hard and it quickly heats up. We fired up Real Racing 3, which is one of our favourite mobile games, and although it plays beautifully, it does make the phone a little warm. The same can be said for other intensive tasks, such as 4K video capture.

If we're being fussy then there are some areas where we think the Z3 Compact could be faster too. For example, the camera is a little slow to open, previews can be slower to open than you might expect, but otherwise, we think this phone offers a great experience in a small package.

We've been critical of some of Sony's decisions with the Xperia Z line over the past few years, but its attention to battery life, particularly Stamina mode, has been universally impressive. The Xperia Z3 Compact also has impressive staying power, which is really to Sony's credit.

There's a 2600mAh battery within (the Samsung Galaxy Alpha is 1860mAh by comparison) and although it's not accessible, so you can't replace it, there's a good chance you'll never have needed to anyway. The Z3 Compact has been getting us through arduous days no problems - leave the house in the morning and it'll still alive when you crawl in at 3am, even if you're not. Of course that depends on what you do with it (which is true of all phones) as it won't withstand non-stop gaming.

Sony Xperia Z3 Compact review

The Stamina mode is partly to thank for this. It isn't just a screen dimmer and hardware throttle - which some competitors' modes are - but instead gives you granular control over what specific apps are doing. You can elect those apps that you want to have data access in standby, such as messaging apps, so you're only working the parts that need to be worked.

Overall the Xperia Z3 Compact is far better than many competitors in terms of longevity. All thanks to Sony's considered approach to battery life and one that we wish would be more seriously adopted by other manufacturers. Good job.

Sony has made a lot of noise around sound quality on recent devices. The Sony Xperia Z3 Compact supports in-device noise-cancellation if you use the Sony NC31E headphones, and with great results as we found with the Xperia Z2. But it also comes equipped with a range of sound profiles for other Sony headphones if you happen to have a pair.

Sony Xperia Z3 Compact review

There's a huge range of audio settings, with ClearAudio+ offering to auto-optimise everything, or a manual equaliser, plus surround sound or S-Force Front Surround options. Then there is high-resolution audio support via USB, as well as the option to change the sensitivity of the mic input.

It's certainly commendable, but if you want the best from the Z3 Compact audio, you'll want to use headphones. The speakers may have moved to the front of the device for this model and they certainly offer plenty of volume, but they're not best in class.

Sony Xperia Z3 Compact review

Turn up the volume and you'll feel the case vibrating and there isn't a huge amount of depth, even if you can get some nice stereo separation. The speakers take up a lot less space than those of HTC's BoomSound, though, which makes for a more compact and friendly design.

When it comes to call quality, we had no problems with the Sony Xperia Z3 Compact. It's a comfortable phone for making calls and no one reported any problems hearing what we had to say.

Like previous models, the Sony Xperia Z3 Compact comes with a 20.7-megapixel rear 1/2.3in Exmor RS sensor for its main camera, and a 2.2-megapixel front camera. There's a whole heap of options to get the results that you want.

A dedicated camera button is something we've always loved about the Sony devices and it continues to be a strong feature in the Z3 Compact - although we wish it was a little faster. A press-and-hold launches the camera app so you can take a shot without unlocking the phone, but when you want to view your shots it seems to take an age to offer you the unlock screen. That's something we alluded to in previous Z-series compacts, so this is an area where some software refinement would help.

Sony Xperia Z3 Compact review

There are all sorts of additional camera settings, but the main shooting mode is Superior Auto. This will try and do everything for you, but does limit some of your choices, including the resolution. Superior Auto snaps at 8-megapixels; if you want the full 4:3-ratio 20-megapixels then you'll have to switch to Manual mode instead.

One oddity about Superior Auto is that it doesn't let you toggle HDR (high dynamic range; to boost shadows and limit highlights). It will auto-detect the scene, but won't always give you a deliberate effect like HDR, meaning that in some high-contrast scenes you'll end up with blown highlights or excessive shadows, rather than a balance of both.

The rear camera is a lot of fun and we like that it can deliver results in pretty much any situation. It offers higher ISO shooting than ever before, aiming to get the shot no matter how little light is available.

Sony Xperia Z3 Compact review

As the ISO sensitivity rises - which is the camera's way of boosting the signal to combat low-light conditions - so does the image noise, that grainy or colour-specked appearance in images. However, we've had some passable shots at ISO 1250 and even at ISO 3200, which is the highest manually selectable setting. There is also a headline ISO 12,800 setting reserved for low-light mode in Auto shooting, but the results, as you might imagine, aren't so great.

Face detection also works well, and having autofocus set to faces is worthwhile to ensure the people who matter are always looking sharp. You can set metering to faces too, but again, Manual mode offers up most of these essentials.

Overall, the Z3 Compact delivers a great camera. We'll be putting it alongside the likes of the LG G3 and iPhone 6 soon to see how they compare side-by-side, but we're impressed with the results we've got from this Sony.

Sony Xperia Z3 Compact review

The front camera is a more average performer though, so if you're into selfies then they are a little lacking in detail. But it's this camera that you'll probably use for face-to-face Skype calls and the like, for which it is fine.

Talking of video, there are plenty of options here too, including 60 frames per second Full HD capture, again requiring Manual mode to be active. There is also SteadyShot technology to smooth out handshake and the "jolt" that can be caught during capture. For example, if you're walking and filming, then SteadyShot counters that movement as a result of each footfall. It's definitely worth using.

Then there is 4K capture, although this is a separate mode, accessed alongside some of the other fun stuff that Sony offers, such as Timeshift video, AR effects and so forth. The results are great and we like the option for future-proofing, but we suspect most will stick to 1080/60p. Do note that these two top resolutions far exceed the Z3 Compact's own screen resolution, so are really designed for presenting elsewhere to get the most out of them.

Sony's take on Android 4.4 KitKat pours in a lot of options, as we've seen in previous Sony re-skins on its other devices. There are heaps of things to choose from in the camera, audio, display and other departments, but despite so many options Sony seems to have organised things well. Head into the settings menu and it all just makes sense - so even first time users will get along with this phone swimmingly.

There are still a lot of additional apps added by Sony and your take on that might be good, it might be bad. If you're already a user of Sony's services such as Music Unlimited then this might appeal, but if not, you can settle down and hide such things in a folder - probably one created and marked "bloatware" - in the apps tray.

Sony Xperia Z3 Compact review

Refinements include Sony's Album which is starting to ape some of the features of HTC's excellent Gallery app, including summary videos and a changing top photo display that pulls pictures from the past - a great way to reminisce.

We also like the Walkman app. If you're a Music Unlimited customer it plugs right into the app, serving up things like the charts and a range of connected features. You can turn it off if you'd rather just stick to local music, however.

Sony's What's New sits as a shortcut next to Google Now, waiting to suggest a collection of Sony content for you to consume, but whether this will be useful for you comes down to how tied-in to Sony services you are already. We found it easy enough to ignore, so it isn't too invasive.

Sony Xperia Z3 Compact review

We've also found the default keyboard good. It offers fast typing action, with trace, predictions and all the usual tricks. There are also emoji available, although we've found that some of what Sony offers isn't always supported at the receiving end - so when you type "pizza" and are offered a pizza emoji, think twice about selecting it as the person you're talking to will probably just receive a blank space.

Overall, Sony is showing that it's learning software lessons with its Xperia devices. The Xperia Z3 Compact feels like it's evolved, matured, and better than before - and a great companion for those deep into Sony services.

Lastly there's a very cool feature, although one that's not yet active: PS4 Remote Play. This means you can use your Xperia Z3 Compact in place of a PS Vita to play your PlayStation 4 games when the service goes live in November. Yet another reason to buy the console? That's what Sony is hoping.

Sony is selling an accessory so you can attach the phone to a DualShock controller, so you'll then be able to use the device as the display. It's not live yet, so we haven't had the chance to test it out, but it's an exciting prospect - and potentially much better than the PS Vita experience currently offered. Saying that, the Xperia Z3 with its larger screen and higher resolution is likely to be the device to opt for if this feature has you hooked a significant selling point.

Verdict

There's so much to like about the Sony Xperia Z3 Compact. It's one of few devices as powerful at this size, offers great battery life, is well designed and fully packed with features. Sony's pricing at £429 undercuts the rival Samsung Galaxy Alpha by a considerable margin, making it an even more enticing proposition.

As much as we love the Z3 Compact and almost everything it does, there are still some small niggles. It arrives just over six months after its predecessor, there's some software overkill, the camera app doesn't load as fast as we would like, and the screen still isn't best in class despite doing a decent job.

We also can't help but look at the larger Sony Xperia Z3 and its more resolute display - bigger movie playback, more gaming space, a better browsing experience also sounds enticing - but then there's the inflated cost to consider.

But it's that last thought; that lure to the larger screen that also highlights just how good the Z3 Compact is. Because whatever your preference, big or small, Sony is offering a choice without having to worry about sacrificing performance. Like the Sony Xperia Z1 Compact, the Z3 Compact is a great - and importantly a little - flagship handset. We're yet to see a better Android device at this size.