Smove look at controler

So im trying to make a camera system where you look at an object and orbit around it and run smoothly this is my code

	GameObject target;

	void Start(){
		target = GameObject.Find("Player");
	}

	void Update(){
		this.transform.LookAt (target.transform.position);
		transform.RotateAround (target.transform.position, new Vector3(Input.GetAxis("Mouse Y"), Input.GetAxis("Mouse X"), 0), 150 *              Time.deltaTime);
	}

im trying to get it to not flixer when you look some directions and to be apple to zoom in and out of the object

BTW i already read ever answer and forum post about this subject and i still got nowhere, ive been working on this for 3 hours new

bump