The Sony Xperia Z2\u00a0is Sony's new flagship smartphone. It takes the Sony Xperia Z1\u00a0launched in August 2013 and refines it, with Sony running with the message that "details make the difference".Sony continues to leverage its wide experience in consumer technology, this time looking to bring lessons it has learnt from its Handycam camcorders with enhanced video capture in the Xperia Z2, among other features.\u00a0Familiar designThe design is strikingly familiar, reflecting exactly what you expect from the Xperia Z family: it matches previous handsets, but slips in nicely among the new Sony Xperia Z2 Tablet and the Sony Xperia Z1 Compact, with the same, flat, OmniBalance design.The phone is constructed from a solid aluminium frame, with those neat chamfered edges, and\u00a0a tempered glass front and rear panel. There isn't much to differentiate it from the Xperia Z1\u00a0from the outside\u00a0but there are changes.The phone is now slimmer (not as wide) and lighter. The difference in weight is noticeable when you hold both at the same time, which addresses one of the concerns we had of the Xperia Z1 when we originally reviewed it. It's now 8.2mm thick, 0.3mm thinner than before.However the increase in the screen size to 5.2-inches means this smartphone is marginally taller than before. Whichever way you look at it, this is still a large device, although we don't have final measurements. There's still a healthy width of bezel above and below the display that seems superfluous. If you were happy with the size of the original Z1, then you'll have no concerns here.The Sony Xperia Z2 continues the trend with waterproofing but, as always, you'll have to contend with the flap covering the Micro-USB charging port.\u00a0The 3.5mm headphone socket is open and proofed as before, however, and there is a magnetic charging connector on the side, so if you opt for the dock, those flaps won't be a concern.The hardwareSitting under the skin of the Sony Xperia Z2 is the latest 2.3GHz quad-core Qualcomm Snapdragon 801 partnered with 3GB of RAM, so the Xperia Z2 is a veritable powerhouse. That's reflected in the slick and smooth operation, although we didn't have the chance to really set the Z2 to task in our demo time.You get all the connectivity you'd expect, as well as microSD card support and powering the whole thing is a 3200mAh battery. We've been impressed with battery performance from recent Sony Mobile devices, with the Stamina mode options giving you plenty of control over which apps will be drawing power in standby and so on.Improved display\u00a0The Xperia Z2 display adds to the Triluminos and X-Reality labels with Live Colour LED. The new proprietary Sony technology adds red and green phosphors to the IPS LED display to again widen the colour gamut. Sony claims that Live Colour LED allows you to boost colours without oversaturating.First impressions of the display are good. There's punch in those colours and we've long appreciated what X-Reality brings to photos and video, but with limited material and time, it's difficult to make a final assessment of its performance. One thing is clear: the viewing angles are much better than before.\u00a0The resolution hasn't changed however. With 1920 x 1080 pixels, 423ppi on that 5.2-inch display, there's plenty of detail, but Calum MacDougall, director\u00a0of Xperia marketing at Sony, was quick to say "our view is that Full HD is the right resolution for the human eye" on this size of device.Camera enhancementsYou get the same 20.7-megapixel Exmor R for Mobile sensor on the rear of the Xperia Z2, but Sony is looking to enhance the experience with 4K video capture. That's an expected move from a company that also offers 4K camcorders and televisions, as it forms part of Sony's 4K creation story.The display, naturally, won't show you all that detail, but cleverly, you can capture 4K and play it back on the device, with the freedom to zoom in on a particular area of interest and still be able to watch that detailed area in Full HD without a loss in resolution.This also works through the MHL output via the USB connection, so you can play 4K content on a big screen, or again, zoom in to something that's of interest.It's not only 4K capture - and a new selection of video effects, like AR and Vine - that's on offer. The Sony Xperia Z2 now offers SteadyShot image stabilisation. This is a digital stabilisation system, but it works on a number of axis, designed to take the wobble out of walking, for example.\u00a0We've seen it in action in a demonstration on a wobble plate from Sony and it seems to make a difference, but we'll have to test it in the real world before we can pass a judgement on it.Sony is also bringing 120fps slow motion to the Xperia Z2. Like the iPhone 5S, you'll be able to capture the footage at 720p and slow down the sections you want in slow motions. The interface is simple and intuitive and the results look great.The camera is very much what you'd expect form the Z2, with lots of options available. The quality, from what we've seen looks pretty good, with a new "background defocus" mode for stills shooting doing exactly what it says on the tin.Sounding betterThe Sony Xperia Z2 moves the speakers to the front of the handset, aiming to give you some of that great stereo effect that the HTC One has enjoyed over the past year. This time it's called S-Force Front Surround. We didn't have much of a chance to test the performance in our preview time, so again, we'll have to wait for a full review before we can definitively assess the speaker's skills.However, one addition we did get the chance to test was the new noise cancellation system that Sony is bringing to the Z2. This works in partnership with the Sony MDR-NC31EM headset that will be bundled in the box for Z2 handsets in the UK.As with existing noise cancelling headphones, there are small mics on the earbuds that detect ambient noise. This is fed to the phone that then adds counter-noise to cancel it out. There are three levels of cancellation, and Sony claims it will cancel out 98 per cent of background noise.Sony says this is the first handset to incorporate noise cancellation of this type, but you have to use Sony's headphones to make it work. We've tested it and it seems effective.READ:\u00a0Sony adds digital noise cancellation to Xperia Z2 and Z2 TabletSoftware and user interface: What's new?There is a range of tweaks that arrive with the latest version of Sony's skin, layered over the top of Android 4.4 KitKat. It's great that Sony is launched with an up-to-date version of Android, incorporating the translucent notifications bar and other elements.However, there's an addition that we're not sure will be so popular. Sony has added a shortcut to What's New into the swipe action used to access Google Now. What's New is a portal that pushes Sony's own content and giving it prominence in such a way feels a little too intrusive. If you generally try to avoid bloatware, this is really going to be in your face if you're a Google Now user.We've mentioned the tweaks and changes in the camera and there are small additions, including the Navigon satnav app that wants to take the place of Google Maps navigation, but after the free trial, you'll have to pay for it.\u00a0We didn't have the time to explore every change to the interface, but things look and feel very much as they do on other Sony Xperia devices.First ImpressionsOverall, the thing that left the biggest impression on us was the display. The colours look rich and vibrant and complement the otherwise solid build of the handset. It's still on the large side, however, and with devices like the LG G2 offering the same display size and resolution in a smaller package, we still feel that the Xperia Z2, like the Z1, is bigger than it needs to be.The Sony Xperia Z1 was a powerful device and the Xperia Z2 takes things up a mark, making this one of the most powerful Android handsets around. There are improvements we're eager to test out, like the new video features, and to see just what sort of battery performance we get from Sony's new flagship once we get it in for a full review.The Sony Xperia Z2 will be available from March 2014, pricing still to be confirmed.