The Z1S is no slouch when it comes to stamina: With its 3000mAh battery, the phone has been able to get me through full days of moderate to heavy use without ever breaking a sweat. I've consistently gotten a solid three to four hours of mixed-usage screen-on time while ending the day with at least 30% of the battery remaining.
The Xperia Z1S comes with 32GB of internal storage, about 26GB of which is actually available to you after factoring in the operating system and various preinstalled applications. The phone also has a microSD slot that allows you to add up to 64GB of external space.
Call quality has been A-OK on the Z1S for me, though I have found the phone to be a bit awkward to talk on. Its earpiece is located at the very top edge of its face, all the way above the bezel — so you basically have to tilt the device and hold the top edge against your ear in order to hear clearly. Especially given the size of the device, that's rather unnatural to do.
Data speeds, meanwhile, have been peachy: The phone supports both LTE and HSPA+-level T-Mobile 4G connections. In my area, where HSPA+ is the best option available, I've been getting around 15Mbps downloads with the device.
Sony's putting a lot of focus on the Xperia Z1S's camera, proudly touting that the phone uses a 20.7-megapixel shooter along with its special "G Lens" and "Bionz" processing engine. That's a lot of marketing-speak — so how does the thing actually perform?
In short, pretty darn well; I'd easily rank the Z1S among the top Android camera phones available today. I wouldn't put too much stock in the big megapixel number alone — all that means is that the camera can capture very large images and, in fact, the Z1S sticks to 8 megapixels by default — but with all the pieces put together, you've got a respectable setup by smartphone standards.
Images I've captured with the Xperia Z1S have generally had sharp detail, true-to-life colors and a minimal amount of noise in the background. The latter element in particular is a quality many smartphone cameras fail to achieve.
The Z1S has also shown itself to be unusually good at shooting moving objects without adding much motion blur — another area where most smartphones tend to struggle. And it's held its own more than I expected in low-light conditions: While it can't keep up with the clarity of the HTC One in that department, the phone is able to get reasonably decent-looking shots in extremely dim environments.
The Z1S's pictures aren't perfect: They sometimes err on the side of being a little dull and washed out, and I can occasionally detect visible artifacting around objects' edges if I zoom into an image and study it in full resolution. But most users aren't going to notice that sort of stuff. For casual photo-taking purposes, the Z1S does a commendable job.
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