Ever wonder why your camera fail to focus tact sharp on your intended subjects at times? Screwed up contrast management in AF module due to insufficient light. Here's when your AF illuminator fires up. Right, its only up to 3m in range. So, don't go away thinking this wonder light to reach anything beyond that!
One more surprise I found - remove the lens hood to use it effectively on any lens with a 24-200mm focal length! Gotcha! I was surprised too. See page 55 of your manual.
Want a break from this limit? Get the Nikon SB-900 to throw the AF capability further via its built-in AF-Assist Illuminator!