It is pretty soft at 2.8 and toward the smaller end of the aperture range it loses some sharpness also. Like almost all NEX lenses, there is no real focusing ring which can be a pain in the ass when the AF craps out (this is more of an issue on the longer lenses though). The build quality isn't that bad with it's metal mount and body, there are no sounds when shaken, and overall just doesn't feel as dinky compared to something like any 18-55 from any dslr. One thing to note is that the finish of it (and some other NEX lenses) is some odd laser-etched-to-look-like-brushed metal finish. If you scratch your fingernail across the finish it will be like sandpaper on your fingernail. This finish easily scratches the screen if the two come into contact in your bag.
Here is an example of the 16mm at f/2.8, ISO 200, JPEG, unedited. it was a 20s exposure, so some loss of sharpness was due to wind. (sorry for sideways)
Here is an example at f/16, ISO 200, JPEG, unedited.
So neither of them are suuuper sharp, but they get the job done and can make some striking images for a great price and size too.
By the way, my NEX setup is a NEX c-3 with the 16mm and the 55-210mm. With the 16mm, it is really my only camera that I can take with me anywhere without wanting to lug around a bag or have it around my neck at all times
