Attached Link: http://ockhamsbungalow.com/Python/ZoomToExtent.zip

This was suggested by Maclean a few days ago. If your camera has drifted way out of range, or you suspect an object is somewhere in the scene but not findable, you can just click on this ZoomToExtent script. The currently selected camera will zoom out or in, and slide left or right, until its view field includes all the "solid" objects in the scene. (By "solid" I exclude GROUND, lights, cameras, etc.) This is a first draft; it works only on Main and Aux cameras, and works fairly well but not perfectly. See the readme for more detail.

My python page
My ShareCG freebies