I am going to purchase one of these three cameras. They all produce great photgraphs, obviously, leaving it up to the photographer to be an artist with the tools provided. I'm wondering which of the three make it easier to either change settings that are wanted or gain information. For example, is there much difference for: Exposure compensation + or - DOF preview AF point I assume changing aperture or ISO or shutter speed is about equivalent on all three -- is that so? Thanks for your advice.