Sony has tweeted another tease ahead of its Xperia Z1 unveiling,the Xperia Z1 will be following in the dripping footsteps of the Xperia Z as another waterproof smartphone. The, ahem, focus then went on the camera lens and LED flash. Then to the dedicated shooting button – suggesting the camera should be something special.With rumours of a 20-megapixel snapper, and potentially even 4K video, expectations are high. But with Nokia's Lumia 1020 sporting that 41-megapixel camera and Samsung rumoured to be unveiling a 4K video recording Galaxy Note 3, Sony has its work cut out for it.www.techandgadge.