Orbit/Pan/Zoom target problem.

[AddComponentMenu("Camera-Control/3dsMax Camera Style")] public class maxCamera : MonoBehaviour { public Transform target; public Vector3 targetOffset; public float distance = 5.0f; public float maxDistance = 20; public float minDistance = .6f; public float xSpeed = 200.0f; public float ySpeed = 200.0f; public int yMinLimit = -80; public int yMaxLimit = 80; public int zoomRate = 40; public float panSpeed = 0.3f; public float zoomDampening = 5.0f;

 private float xDeg = 0.0f;
 private float yDeg = 0.0f;
 private float currentDistance;
 private float desiredDistance;
 private Quaternion currentRotation;
 private Quaternion desiredRotation;
 private Quaternion rotation;
 private Vector3 position;

 void Start() { Init(); }
 void OnEnable() { Init(); }

 public void Init()
 {
     //If there is no target, create a temporary target at 'distance' from the cameras current viewpoint
     if (!target)
     {
         GameObject go = new GameObject("MainCamera");
         go.transform.position = transform.position + (transform.forward * distance);
         target = go.transform;
     }

     distance = Vector3.Distance(transform.position, target.position);
     currentDistance = distance;
     desiredDistance = distance;

     //be sure to grab the current rotations as starting points.
     position = transform.position;
     rotation = transform.rotation;
     currentRotation = transform.rotation;
     desiredRotation = transform.rotation;

     xDeg = Vector3.Angle(Vector3.right, transform.right );
     yDeg = Vector3.Angle(Vector3.up, transform.up );
 }

 /*
  * Camera logic on LateUpdate to only update after all character movement logic has been handled. 
  */
 void LateUpdate()
 {
     // If Control and Alt and Middle button? ZOOM!
     if (Input.GetMouseButton(1))
     {
         desiredDistance -= Input.GetAxis("Mouse Y") * Time.deltaTime * zoomRate*0.125f * Mathf.Abs(desiredDistance);
     }
     // If middle mouse and left alt are selected? ORBIT
     else if (Input.GetMouseButton(2))
     {
         xDeg += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
         yDeg -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;

         ////////OrbitAngle

         //Clamp the vertical axis for the orbit
         yDeg = ClampAngle(yDeg, yMinLimit, yMaxLimit);
         // set camera rotation 
         desiredRotation = Quaternion.Euler(yDeg, xDeg, 0);
         currentRotation = transform.rotation;

         rotation = Quaternion.Lerp(currentRotation, desiredRotation, Time.deltaTime * zoomDampening);
         transform.rotation = rotation;
     }
     // otherwise if middle mouse is selected, we pan by way of transforming the target in screenspace
     else if (Input.GetMouseButton(2))
     {
         //grab the rotation of the camera so we can move in a psuedo local XY space
         target.rotation = transform.rotation;
         target.Translate(Vector3.right * -Input.GetAxis("Mouse X") * panSpeed);
         target.Translate(transform.up * -Input.GetAxis("Mouse Y") * panSpeed, Space.World);
     }

     ////////Orbit Position

     // affect the desired Zoom distance if we roll the scrollwheel
     desiredDistance -= Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * zoomRate * Mathf.Abs(desiredDistance);
     //clamp the zoom min/max
     desiredDistance = Mathf.Clamp(desiredDistance, minDistance, maxDistance);
     // For smoothing of the zoom, lerp distance
     currentDistance = Mathf.Lerp(currentDistance, desiredDistance, Time.deltaTime * zoomDampening);

     // calculate position based on the new currentDistance 
     position = target.position - (rotation * Vector3.forward * currentDistance + targetOffset);
     transform.position = position;
 }

 private static float ClampAngle(float angle, float min, float max)
 {
     if (angle < -360)
         angle += 360;
     if (angle > 360)
         angle -= 360;
     return Mathf.Clamp(angle, min, max);
 }