How did you have your camera set up? Centre focus only is far better in poor light as more sensitive than the other focus points. I find it varies depending on which lens is attached as well even if they have the same f-stop with one hunting and the other locking on easily. Also your mate may have been using the old trick of focussing on something near the subject with better contrast, say the edge of a tree trunk next to the stag or on the antlers rather than the main body of the animal. Nikon better than Canon at focussing? No way
. Andy Rouse chose Canon because of the better focussing!
