Modern professional DSLRs can be customized in nearly every aspect of their operation. My Canon EOS-1D X
While it is fun to play with the settings, I find, in practice, that knowing which settings are most critical for particular types of shots and learning how to change them quickly during a photo shoot is sufficient. In fact, it is simply not practical to fumble through all possible variations of settings in order to potentially find the optimal combination. Most likely, doing so will result in missing a shot.
I find that it is useful to become familiar with just a few camera configurations and to learn (through experimentation) which ones do not work for a particular situation. Having said this, I try to re-visit the manual periodically and to make sure that I am fully utilizing the capabilities of the camera.
