Check how far and if the object is in view and do something.

I want to make it so when the object is so far away and is in view to switch cameras and to animate then when the object is out of view of to far away to stop animation. this would be a great help here is my script so far.

it detects how far away and if the object is in view great but i need the other functionality to.

 #pragma strict
 
 var other : Transform;
 var anObject : GameObject;
 private var cam : Camera;
 private var planes : Plane[];
 
 function Start () {
 
 }
 
 function Update () {
     
         //Detects how far away the object is
     if (other) {
         var dist = Vector3.Distance(other.position, transform.position);
         print ("Distance to other: " + dist);
     }
     
         // Detects manually if anObject is being seen by the main camera
     cam = Camera.main;
     planes = GeometryUtility.CalculateFrustumPlanes(cam);
       
       if(GeometryUtility.TestPlanesAABB(planes,anObject.collider.bounds))
             Debug.Log(anObject.name + " has been detected!");
         else
             Debug.Log("Nothing has been detected");
     
 
 }