Sony Xperia Z : A Waterproof and preposterously high-resolution gadget

We are all led to believe that size isn't everything. So when you learn that Sony's Xperia Z smartphone has a 5in screen, you'll know that this means it's big but not necessarily beautiful. In fact, it's both, not least because that screen is preposterously high-resolution.
The 5in display has as many pixels as a 55in Full HD flatscreen TV. That's around 2 million, if you're counting.
I previewed the Xperia Z a few weeks back, but it's time for a proper review now the final units are on their way to the shops - out on 28 February.
The Xperia Z also looks good because the design is simple to the point of discretion. Save for the Sony logo, the front of the phone is one black rectangle with gently curved edges. The back is similarly plain, though with the word Xperia on it.
This understated look, which works on all three colour versions of the phone (white, black and a purple option that's exclusive to O2) is classy, and because the phone is actually very slim — 7.9mm — it doesn't feel as mammoth in your hand as you might think.
Pretty pixels
The display, with its 443 pixels per inch, is bright and colourful without being over-saturated, shining most when you're reading text which looks pristine. The screen's visuals are given a lift by technology poached from Sony's Bravia TVs. Video playback looks terrific, as do photos you've shot on the handset's camera which, with its 13MP resolution sensor, is no slouch. More pixels don't always mean better pictures: small sensors crammed with the tiniest of pixels find it difficult to suck in enough light to make sense, leaving photos with that grainy image noise so common on smartphone snappers. But Sony is skilled with cameraphone technology and the results here are strong.
There are Sony specialities like Sweep Panorama for easy, impressive widescreen shots - Sony had this technique down long before the iPhone 5. And Smile Shutter, which recognises when your subject is breaking into a grin and automatically takes its shot for maximum smile without you even having to touch the phone. And it shoots video at full 1080p resolution, too.

Battery life
A big screen means you'll need some power to keep it lit up, not to mention to service the quad-core processor as it zooms along. All this on an Android phone - an operating system which is known for running programs in the background and reducing battery life.
But the battery is not removable, so the space is taken up with minimum packaging and maximum juice. And there's a Stamina Battery mode to eke out the most power. Turn on this mode and a lot of the phone shuts down: WiFi, Bluetooth and mobile data are disabled, though calls and texts will still come through and any software that's mid-download will finish before the data connection cuts out. Alarms will still work, too. These changes happen as soon as the screen turns off, and are re-enabled when you start using the phone again. How much does it help? Well, if the calculations on-screen are accurate, it can boost the remaining standby time from eight hours to two-and-a-half days. Whatever the exact figures, it certainly helps.
Even without Battery Stamina, the Xperia Z seems to last a full day happily, though for peace of mind I'd still recommend nightly charges.
4G
This is a 4G phone. For now, that means it's capable of high speeds only on the EE network, though the frequencies built into the phone mean it will be 4G-compatible on other networks, after the current frequency auction is concluded.
One network, Vodafone, has said that customers buying now can be switched to 4G when it arrives. The company is currently taking pre-orders for the phone and the first 1,000 customers will receive a £299 pair of Sony headphones free. The headphones are the company's impressive MDR-1R cans and are worth having.
Waterproof?
Oh yes, and the phone's waterproof. I put it under water to test this. Which is a scary thing to do, frankly, but there was no problem. All the holes (power, headphone, SIM card slot) have plastic flaps which clip into place. They're a little fiddly but they work well.
Let's be clear, there's no texting underwater to be done here. The nature of capacitive touchscreens is that they work by a weak electrical field on the surface of the phone being interrupted by another electrical field like your finger. So if the screen is drenched in water this just doesn't work. The key thing is that once you've retrieved the phone from the bath, or whatever receptacle you dropped it into, the Xperia Z should still be fine. In my tests, it was.
This is Sony's classiest, neatest and biggest phone yet. It's full of innovations, has excellent, quiet styling and is enjoyable to use. This is a striking, well-crafted, highly appealing phone. If your hands are big enough.