I am unable to get consistently good sharp pictures with my t4i even though I use a tripod. It seems that the auto-focus area is too large and it picks up and focuses on an object in a different plane. Is there any way around this - other than using manual focus? An example might be a bird on a branch in a tree where a foreground branch is in focus but the bird is not. I revert to live view and zoom in to focus manually but by the time I do this, the bird hs flown away.