Comments about Sigma Sigma 30mm f/1.4 EX DC HSM AutoFocus Standard Lens for Sigma Digital SLR Cameras.:
This lens came with the dreaded auto-focus problem. [...] - but I called Sigma and they agreed to fix it. Sigma was friendly - was on the phone < 5 min with them. I sent it to Sigma and got it back a week later. Now it autofocuses great! Takes a little longer in low light to focus - better to choose the auto-focus area.
(I used it on my Canon 20D, F/W 2.0.3)