So far, I've given examples of shooting in heavy brush. Now my favorite spot consists of three environements: Open beach, Thick woods and brush, and and a fantastic marsh covered in eel grass. One of the best series of pictures I've ever shot was taken of a mother and baby Clapper Rail. The series consisted of a dozen shots. The middle shots of this series would have given AF no problem at all. Here's a shot from the middle part of the series.
But what about the beginning of the series?
How could I pick out Mom and not the kid, or vice versa? Indeed, AF would have a hard time with the eel grass as it is.
And then there was the end of the series. How well would AF work in this situation as shown by these two photographs?
To sum up here, basically on this occasion I was shooting in an open environment, an environment where AF shouldn't have to many problems. But an unanticipated opportunity occurred. Why should I handicap myself by waiting for AF to "seek" and avoid objects before or after my subjects? No doubt this could be overcome - How much time would this take? And this opportunitiy was over 15 seconds later.