I only have problems in low light conditions or for macro shots where there is too much of the same colour for the autofoucs system to determine the right focus. Shots that are blur were due to my own fault (shaky hands).
Maybe you are trying too hard . Just make sure you press the shoot button half-way to allow the camera to confirm the focus before depressing it fully.
I took the shot last Saturday afternoon at Marina bay, so the light condition is not an issue.
However I suspect it could be due to my aggressive use of zooming unnecessarily¡K