Camera dont move whit Smooth Follow 2D

Im try use the Script of this post in my project(http://answers.unity3d.com/questions/29183/2d-camera-smooth-follow.html) in C#, but when i add in my project and add my Target dont happen anything, i will post the script here to see best:

CamDown.cs using UnityEngine; using System.Collections;

 public class CamDown : MonoBehaviour {
 
     public float dumptime = 0.15f;
     private Vector3 velocity = Vector3.zero;
     public Transform target;
 
     // Use this for initialization
     void Start () {
 
     }
     
     // Update is called once per frame
     void Update () {
         if (target) {
 
             Vector3 point = Camera.main.WorldToViewportPoint(target.position);
             Vector3 delta = target.position - Camera.current.ViewportToWorldPoint(new Vector3(0.5f, 0.5f, point.z));
             Vector3 destination = transform.position + delta;
             transform.position = Vector3.SmoothDamp(transform.position,destination, ref velocity, dumptime);
             Debug.Log ("Esta aqui");
         }
     }
 }

in script of the post he use the camera variable, im try change to Camera.main and Camera.current but nothing happen, please help me, thanks much.