>>4087766you just use the A setting on the dial to turn a setting automatic. so P = shutter speed and aperture on A; A = shutter speed on A, aperture dial manually set; S = shutter speed manually set, aperture on A; M = shutter speed and aperture manually set. you don't have to worry about modes, you just set what you want to set and set what you don't to A.
I'd recommend looking at the dpreview article on any camera you're looking at to help answer these questions. you can also check out the product page for spec questions.
