I was excited. There are a lot of good things being said about these Sigma lenses. On my way home from picking up the lenses, I put on the 19mm f2.8, and shot a few frames. The very first frame is what you see here. I am happy I bought them. It's optically excellent, albeit a bit slow with an f2.8 maximum aperture.
One thing almost gave me a heart attack was the noise from these lenses. I didn't notice it when I put on the 19mm, but when I got home, as soon as I took the 30mm f2.8 out of the box, I heard something moving inside. Not just a small sound, but it feels and sounds like a large part is loose inside the lens. I was swearing inside, thinking the lens had to be returned. Quickly I put on the 30mm and tried it on the NEX-6. Not a problem at all. Focused fine, picture is razor sharp at f2.8. Then I lightly shook the 19mm and sure enough, it makes the same noise as the other lens. The noise is very disconcerting. A quick search indicates that the noise comes from the linear motor; when no power is applied, some of the lens elements float. Phew!
Curiously, the 19mm f2.8 comes with a lens hood, but not the 30mm f2.8. This is very unusual. The normal Sigma way of doing business is that every lens, regardless of how cheap, comes with caps, hood, and a nicely patted lens case. This puts certain lens maker to shame; unless you pay a premium for lenses that have a red ring, no hood and lens case for you!
Jimmy Simpson Park - NEX-6 & Sigma 19mm f2.8 wide open.