Hi guys, i have been reading a couple of articles and videos on how to get tack sharp images. And the information i gather shows that if i were to use Auto-area AF, and while doing a group shot , 9 AF points lights up.. it does not mean that all these 9 points will be focused on, because the camera can only focus on any 1 point at a time. It simply means that the camera has managed to 'guess' that out of these 9 points, one of them will be the intended focal point.
So if i want to great a nice tack sharp group photo. I would simply use single point AF, with a smaller aperture (f8-f11), make sure my shutter speed is at least 1/125 (1/100-1/125 seems ok), iso100. that would do the trick too right? even though it is a single-point af, it doesn't mean that the person which i focused on, will be the sole person who is sharp in the picture. The sharpness would depend on the aperture sized used, focal length of my lens and the distance between me and the group.