Does this piece of advice make sense to any of you?
Go into the Menu, scroll down and set the AF Zone to "Center Zone". As you say, using a tripod or other steady camera rest, such as a bean bag, is essential. I would also recommend going to the Menu and change the ISO setting to 80 or 100. That will give you the best image quality, but the shutter speed will be slower thus making the tripod/rest essential.