Sniper scope zoom variances

ok so i found a script online and modified it a little uses 2 cameras approach, but what i want is to play a zoom animation raise then reverse anim to lower gun but when the raise anim is finished it would then flicker to the scope zoom how would i make this nice transition a little stuck on it.

function Start () {

Camera1.enabled = true;

Camera2.enabled = false;

}

var Camera1 : Camera;

var Camera2 : Camera;

function Update () {

if (Input.GetMouseButton(1)) {

Camera1.enabled = false; Camera2.enabled = true;

//animation.Play("ZoomIn");

} else{

if(!Input.GetMouseButton(1)) { Camera1.enabled = true; Camera2.enabled = false; } }

}