smooth follow unity 2D

using UnityEngine;
using System.Collections;

public class SmoothFollow : MonoBehaviour {

    public Transform target;    // The target we are following
    public float positionDamping;

    private Vector3 deltaPos;

    // Use this for initialization
    void Start () {
        deltaPos = new Vector3(-4f, 1f, 0f);
    }

    // Update is called once per frame
    void Update () {

    }

    public void FixedUpdate () {
        Vector3 targetPosition = target.position - (Vector3.forward * 10);

        //transform.position = Vector3.MoveTowards(transform.position, targetPosition + deltaPos, positionDamping * Time.deltaTime);
        Camera.main.transform.position = Vector3.Lerp(Camera.main.transform.position, targetPosition + deltaPos, positionDamping * Time.deltaTime);
    }
}