Fantastic wide-angle for the price!
I have been using the 16mm f/2.8 E-mount Sony lens for about two years now and for the latter year coupled with the great wide-angle adapter VCL-ECU1 that essentially converts the 16mm to 12mm.
There are many detractors concerning this lens, however, few seem to account for the cost vs. performance. Basically, for less than 150$ one gets a 24mm equiv. (35mm format) wide-angle lens that is small, light weight and pocketable. Certainly, wide open at f/2.8, the optical performance shows deficiency, such as chromatic aberration and edge distorsion, but the fact is one has f/2.8 available for low-light situations. I would not use f/2.8 in good lighting or for landscapes. Considering the package one gets for the price, I would say the lens is unbeatable. It is essentially a pancake wide-angle lens with f/2.8 aperture! It is implied that there would be drawbacks in a package such as this but considering the low sums it goes for, it is truly spectacular.
The lens shines from f/5.6 to about f/8 and it is very usable for family snapshots, landscape and even cityscape work. The focus is pretty fast but not always very accurate (especially in low light), although, using the DMF mode, it generally works consistently. At all apertures, the center is fairly sharp, a feature that works out in many shooting scenarios.
Coupled with the wide-angle adapter, the optical performance seems to improve, as many have noticed. To add to that, the adapter only doubles the length of the overall package, which is a feat in itself, keeping a low profile for the combination.
I like the lens so much that it is the only Sony E-mount lens I currently own. I like the size and the fact it makes for a truly take-anywhere combination with any NEX, especially with the 5/N/R.
I would have enjoyed a less plastic-fantastic build, although, to be fair, the lens mount is metal. I would buy a black version of this lens, if they ever decided to make it, for the simple reason it would make the combination with a black camera body even more unobtrusive. Perhaps the optical quality could be slightly improved, especially on the chromatic aberration side, which, at times, especially in strong back lighting, can be somewhat annoying.