I just got my new Sigma 30 mm f/1.4 today from B&H. Still testing, but I may have some issues with it.
I did the battery test with five AA batteries touching and photographed them at various angles at f/1.4 and f/3.2. I focused on the middle battery but the one slightly behind it seemed a bit more in focus. With such a narrow depth of field, the two front ones were way out of focus. At f/3.2 the back focusing was still slightly noticeable but a lot less obvious, I suppose due to the greater DOF. Will play with this some more and provide examples when I have more time.
I also noticed that at f/1.4 there seemed to be much more of a halo effect or perhaps its CA around objects such as the white printing on a black lens. This was very noticeable at a 100% crop, but much less so when viewing images full screen on my 23" monitor. At around f/2.2 this seemed to go away.
The real question to me is if i have issues does it make more sense to send it back and get a new copy from B&H or send it to Sigma for calibrate it. The next one from B&H could also have issues. Will Sigma properly identify and fix issues with this lens? I've generally heard good reports. I just spoke to them and they said I don't have to send in the body, although some people seems to. Any thoughts?