camera shaking

i want let camera move follow the character by smooth time.
but it is shaking when used Mathf.SmoothDamp.
here is the code.
player:

using UnityEngine;
using System.Collections;

public class playerControl2D : MonoBehaviour 
{

        public bool faceRight = true;

	public float moveForce = 15;  
	public float maxSpeed = 1f;

	private bool grounded = false;
	private Transform groundCheck;



	void Awake()
	{
		groundCheck = transform.Find("groundCheck");

	}

	void Start ()
	{
		// set animation speed
		animation["idle"].speed = 0.5f;
		animation["walk"].speed = 1.2f;
	}

	void Update ()
	{
		// check whether grounded
		grounded = Physics2D.Linecast( transform.position, groundCheck.position, 1 << LayerMask.NameToLayer("Ground"));
 
	}

	void FixedUpdate ()
	{

		float h = Input.GetAxis("Horizontal");

		// move 
		if( h* rigidbody2D.velocity.x < maxSpeed )
		{
			rigidbody2D.AddForce(Vector2.right * h * moveForce);	
			animation.CrossFade("walk");
		}
		// to run by maxSpeed
		if( Mathf.Abs(rigidbody2D.velocity.x) > maxSpeed)
		{
			rigidbody2D.velocity = new Vector2(Mathf.Sign(rigidbody2D.velocity.x) * maxSpeed, rigidbody2D.velocity.y);
			animation.CrossFade("walk");
		}

		// stand
		if( rigidbody2D.velocity.x == 0 )
		{
			animation.CrossFade("idle");
		}

		// face to right
		if( h > 0 && !faceRight )
		{
			Filp();
		}
		// face to left
		if( h < 0 && faceRight )
		{
			Filp();
		}

	}

	// turn the face
	void Filp ()
	{
		faceRight = !faceRight;
		Vector3 theScale = transform.localScale;
		theScale.z *= -1;
		transform.localScale = theScale;
	}


}

camera:

using UnityEngine;
using System.Collections;

public class cameraSmooth : MonoBehaviour {

	public Transform cameraTarget;
	public float smoothTime  = 0.1f;

	private Vector2 velocity;


	void Update ()
	{
		

	 Vector3 newPos = transform.position; 
			newPos.x = Mathf.SmoothDamp( transform.position.x,  cameraTarget.position.x, ref velocity.x, smoothTime );
			transform.position = newPos;
		}

		

   }
}

Do you by any chance have the main camera as a child under the player gameObject? A lot of times that will mess it up. You’ll have to write a script for following the gameobject, instead of making it a child of the player.