Sony has tweeted another tease ahead of its Xperia Z1 unveil. This time it's a video that gives us a closer look at the new flagship smartphone and a 4 September unveil date.

The video also revealed that 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, we're keeping expectations 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.

The leaked specs so far suggest Sony won't have much to worry about. The Xperia Z1 should arrive with a 5-inch 1080p display, while the inside will pack a Snapdragon 800 quad-core chip, 2GB of RAM, 16GB of storage (expandable through microSD) and a 3,000mAh battery. There might even be a 2-megapixel camera for video calls and support for 4G LTE and NFC.

Pocket-Lint will be at the 4 September launch event at IFA 2013 to deliver all the reveal details live.