I have recently changed from cropped body dSLR (Canon 40D) to a full frame beast (Canon 5D Mark II). When I started to shoot with the 5D Mark II I really thought that there is something wrong with the camera because it was so difficult to obtain decent shots especially sharp ones. Well, I did not know enough about the properties of full frame and I think I am still learning how to to use it effectively. For my relief also other people are encountering same kind of problems (and they are better photographers than I am). I hope I will learn some day.