Camera bounce/collision

I wanted to make my camera collide with walls,i was looking for script on Internet but found many useless, i want just simple script. I was trying to use Raycast but it doesn't work as it should, so i created my own method and it works preety well, but when i stand near wall camera start bouncing (it is zooming in and out, in and out...), any ideas how to fix that? I tried delaying zoomout function but it still doesn't look well.

Here is my script:

 var right_camera : GameObject;    
 private var collisionCount = 0;
     
     function Update () {
         
         if (collisionCount > 0)
         ZoomIn();
         if (collisionCount == 0)
         ZoomOut();
 
     }
 
 function OnTriggerEnter () { 
 collisionCount++;    
 }
 function OnTriggerExit () {
 collisionCount--;  
 }    
 
 function ZoomOut () {     
 var step = 3 * Time.deltaTime;
 transform.localPosition = Vector3.MoveTowards(transform.localPosition, right_camera.transform.localPosition, step);
 }
 function ZoomIn () {     
 var step = 10 * Time.deltaTime;
 transform.localPosition = Vector3.MoveTowards(transform.localPosition, Vector3(-1,2,0), step);
 }