Ok, so this is definately a newb question, of which I probably know the answer already and haven't put it together yet... If I have the camera in "Auto" mode, the majority of the controls are locked out (f-stop, speed, ISO, ect). The camera does it all for me. If I have it in "Program" mode, the camera suggests what to use and I can still tweek it. I have the option to change the settings. Is this correct? Are there any more main differences?