Excuse my ignorance but can someone explain in plain english why the camera can't focus at F8.0?
I have a 24-70 2.8L and use F8 all the time... I find it to be the best, sharpest and most natural F-stop for studio work...
Please someone tell me if that is going to affect me or not.
All lenses focus at their maximum aperature. You're lens has a max of 2.8, therefore the autofocus will work splendidly. The camera doesn't close down the aperature until you hit the shutter button (or the dof preview). As long as you don't use teleconverters you should never run into a situation where AF does not work. I would venture to say if you don't know this stuff then you probably shouldn't be getting a 1DX anyway.
I don't think that knowledge excludes anyone from owning a 1DX or any body for that matter. The poster who asked this question is a pro and shoots very fine photographs. If you've never had to run into this situation, ie you don't use teleconverters, then it matters none that you wouldn't know this.