I am a bit confused about the extra menu option for AF-ON. You have an option to Enable or Disable "Out of focus release." If you look at the camera's info, when you push the question button, this seems to apply when the priority is set to "Focus" for either AF-S or AF-C. Why would you want the camera to release the shutter if out of focus when you have "Focus" as your option? What am I missing here?
I was reading Steve Perry's explanation, and it made no sense to me either. He suggested it affects the other focus/release options as well. I need to go back and read it again to make sure I understand what he was saying.
I did try it out. I chose "Focus" in AF-S. I enabled the 'AF-On out of focus release,' put the camera on manual, unfocused, put it back on AF-S, and it shot, but I don't see why you would want to do that.
I didn't attempt all of the other combinations. Maybe tomorrow I'll mess with it.