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.