Couple days ago I was photographing some night scenes with the NEX-6 and the 16-50mm lens. The camera/lens was consistently unable to lock focus so most of the time it just focus itself to infinity, but sometimes doesn't. So I thought, no problem, I would focus the lens by hand. A strange thing happened. When I turn the focusing ring, the lens zooms. It turns out, I had to set the focus method to DMF in the menu. What this does, is that once the camera finishes focusing, you can turn the focusing ring to focus while half-pressing the shutter button. The camera will automatically enlarges the focus area and you can then do the focus fine tuning. Not exactly intuitive like the Canon USM lenses where you just turn the focusing ring to do focus adjustment after the camera achieves AF.
Skylon Tower - Sony NEX-6 & 16-50mm f3.5-5.6 @ 16mm f8. Click for larger.
I also had a chance to put the camera/lens on a tripod. This is the preferred method of testing lenses. I did find that the lens is slightly sharper when used on the tripod, especially on lower speeds. On the wide end of 16mm at f8, the image quality is nearly as good as the 16mm f2.8 pancake lens, especially at the edges where both lenses are about equal. The 16mm pancake is much better corrected for distortion though.
The lens is progressively better as the focal length increases, both in terms of sharpness and distortion. It's very good at the long end of 50mm. Very little distortion and is quite sharp wide open. But then again, wide open is at f5.6.
The American Falls - NEX-6 & 16-50mm f3.5-5.6 @50mm. Slightly cropped. Click for larger.
After a few days of use, my take on the lens is that if you ignore the very bad distortion at 16mm, which Lightroom 4 has a profile for this lens and can correct it easily and quite effectively, the lens is very versatile. The small size and wide angle have a lot of appeal as a kit lens, and it's not too expensive when bought as a kit with the NEX-6. In fact, I am starting to like this little lens.
Light Shades - NEX-6 & 16-50mm f3.5-5.6. Click for larger.