back in the film days you also went out and spent money on a little cartridge aka "Film". Digital days, your camera is the "film".
I don't care what kind of camera/AF/lenses you have, it could be a Canon F1, with L lenses, if you are shooting crappy Fuji Film 800 your photos are going to look crappy, no matter how spot on your exposure is.
I have a 10 year old 80-200 f/2.8L lens, shoots as sharp today as it did back when i got it.