We went shooting again with our Sony Xperia Z1, after the software update late last month which promised better performance for the camera. We're sorry to say that the update doesn't improve the camera's performance in any significant way.
The checkered artifacts still remain. The camera app will still fix focus on the same spot after you tap to focus, even after you take the picture. And of course the software update can't correct for the lens' obvious softness. The camera's strength remains in its rich color reproduction, but we otherwise can't find any reason to change our original conclusion. There are plenty of reasons why you might want a Sony Z1, but camera performance shouldn't be one of them.