Mainly shoot children, want to upgrade Quan Huafu, choose Canon 6d, but all say 6d focus is too slag, is it necessary to upgrade 5d3 directly? 6d focusing

If everyone likes autofocus, then all the so-called photography techniques are floating clouds, and the focus of all cameras is slag. 6d Although the focusing system is not as good as 5d3 and 7d, the central single-point focusing is also good and sufficient. Of course, if you have a budget of 5d3, it's better to do it in one step, so as not to remember that when you buy this. The lens is important, and the avatar behind the lens is more important!