camera script problems and can't see the selected object

 using UnityEngine;
 using System.Collections;
  
 [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 = 0.6f;
     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 (Input.GetKeyDown("f"))
         {
             Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);//从摄像机发出到点击坐标的射线
             RaycastHit hitInfo;
             if (Physics.Raycast(ray, out hitInfo))
             {
                 Debug.DrawLine(ray.origin, hitInfo.point);//划出射线，只有在scene视图中才能看到
                 GameObject gameObj = hitInfo.collider.gameObject;
                 Debug.Log("click object name is " + gameObj.name);
                 if (gameObj.tag == "boot")//当射线碰撞目标为boot类型的物品 ，执行拾取操作
                 {
                     Debug.Log("pick up!");
                 }
                 target = gameObj.transform;
                 transform.LookAt(target.position);
             }
              
            
         }
         else if (!target)
         {
             GameObject go = new GameObject("Cam Target");
             go.transform.position = transform.position + (transform.forward * distance);
             target = go.transform;
             transform.LookAt(target.position);
         }
         distance = Vector3.Distance(transform.position, target.position);
         currentDistance = distance;
         desiredDistance = distance;
  
         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);
     }
     void LateUpdate() {
         if (Input.GetMouseButton(1)) {
             xDeg += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
             yDeg -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;
             //yDeg = ClampAngle(yDeg, yMinLimit, yMaxLimit);
             desiredRotation = Quaternion.Euler(yDeg, xDeg, 0);
             currentRotation = transform.rotation;
  
             rotation = Quaternion.Lerp(currentRotation, desiredRotation, Time.deltaTime * zoomDampening);
             transform.rotation = rotation;
         }
         else if (Input.GetMouseButton(0))
         {
             target.rotation = transform.rotation;         //
             target.Translate(Vector3.right * -Input.GetAxis("Mouse X") * panSpeed);
             target.Translate(transform.up * -Input.GetAxis("Mouse Y") * panSpeed, Space.World);
         } 
         desiredDistance -= Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * zoomRate * Mathf.Abs(desiredDistance);
         desiredDistance = Mathf.Clamp(desiredDistance, minDistance, maxDistance);
         currentDistance = Mathf.Lerp(currentDistance, desiredDistance, Time.deltaTime * zoomDampening);
         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);
     }
 }