It is always difficult to get good depth of field when photographing with telephoto lens. Especially when photographing subjects that are not very far away from you.
I was photographing an iguana in Florida with my lens at 600mm. It was impossible to get both the iguana and the leaves on the tree in focus. At first I was so busy making sure I was getting the iguana’s eye in focus, I didn’t even notice the out of focus leaves. But when viewing the image on the LCD they were glaringly apparent. Watch the video to see how I solved the problem.