Sony's regular Xperia XZ2 is, to put it mildly, underwhelming -- as capable as it is, there's little to recommend it over its rivals. You can't say that about the just-announced Xperia XZ2 Premium, though. The new handset preserves the 4K HDR visuals of its predecessor (this time on a 5.8-inch screen that's 30 percent brighter), but the real centerpiece is the photography. Sony is hopping on the dual rear camera bandwagon with a focus on low light performance: it melds the input from a monochrome sensor (for contrast; 12MP, 1/2.3-inch, 1.55um) and a regular color sensor (19MP, 1/2.3-inch, 1.22um) to capture video at ISO 12,800 sensitivity, and photos at a whopping ISO 51,200. (Huawei's P20 Pro is also claiming similarly crazy high-level ISO options in a forthcoming software update -- we yet haven't tested that either.) We'd be skeptical of Sony's claim that the performance rivals pro cameras, but this might help you shoot with confidence in truly dark environments.
The dual cams also enable the obligatory portrait mode (here called Bokeh) with soft-focus backgrounds, and you can snap shots with just the monochrome sensor if you're going for the classic look. Sony is also promising a better front camera -- you're now looking at a 13MP, 1/3.06-inch sensor that Sony says can take quality low-light selfies.