I've bought the 580 EX flash used, it's my first external flash. And I'm playing around with it to get some experience. One of the problems I've noticed in very dark environments is that the autofocus can't find a point to focus on.
I know there is this "feel" or "probe" (don't know a better english expression for it) flash a camera can trigger to evaluate the light when the real is triggered. Most cameras do this automatic.
However, I fail to figure out how to set the 7D MK2 with the 580 EX II up like that. How can I set it up this way or is there even a better way to get the focus and exposure right without the probing flash?