So yes, all that zooming works as advertised. It's too bad, then, that the sensor setup behind the lens isn't worth writing home about. What we have here is a 13-megapixel, Panasonic-made sensor that mostly yields decent color saturation and an adequate level of detail. Considering how good smartphone cameras have gotten, though, those are table stakes. Pictures shot with the ZenFone Zoom routinely seemed lifeless and indistinct compared with shots obtained with an iPhone 6s or Galaxy S6 (yes, last year's model).

Don't get me wrong. None of the photos were bad; just unremarkable. What's more, low-light performance isn't great. That pesky grain is kept under control fairly well, but the amount of detail drops off pretty dramatically. There's at least a low-light-specific mode that helps somewhat. And it's hard to forget, as the phone frequently nags you to use it.

Zoom lens aside, the phone's biggest photographic asset is its autofocusing system, which uses a laser to lock onto subjects in a fraction of a second. The feature has popped up in a handful of great phones so far -- LG's most recent flagships and both new Nexuses spring to mind -- and it's a fantastic tool for quick, off-the-cuff shots. It's certainly fast at locking onto subjects, which makes the occasional sluggishness when snapping shots all the more frustrating.

Of course, you can take even more control over photos with the Zoom's surprisingly extensive manual settings. Beyond the usual ISO, exposure, autofocus and white-balance controls, you can also fiddle with sharpness and contrast values, as well as bring up a histogram to make sure your photos are well exposed. ASUS' camera interface is also nuanced enough to make you feel like you're using a proper camera, though the lackluster sensor means those controls will only ever take you so far.

Ditto for shooting video. Maybe it's just me, but a modern smartphone with a clear focus on photography -- even one that costs only $399 -- should be able to record in 4K. Instead, the Zoom tops out at 1080p, and you'll be able to use the handy stabilization feature only if you drop that resolution down further to 720p. The Zoom's video prowess is about on par with its photo chops, meaning you'll get perfectly passable (but forgettable) clips.

Before I started using the ZenFone Zoom, I was hesitant: Isn't its single standout feature just a big gimmick? The answer is a pretty resounding no. ASUS has put together a pretty impressive bit of zooming machinery here; it was the sensor itself I should have been more concerned about. Couple that poorly balanced photographic equation with a thick chassis and lackluster performance, and we're left with one serious question mark of a phone. I can see buying it as a curio -- an example of how smartphones are evolving -- but its practical value is limited at best. If you're serious about getting a first-rate smartphone camera, save up a little more and splurge on a Galaxy S7 instead.