Move to touch position

I wrote t$$anonymous$$s script to make the object move to the position, where the player touched. It gets the finger position correctly, but does not change it to world point value. If I were to use the original value, the object would move far away.

 using UnityEngine;
 using System.Collections;
 
 public class Player : MonoBehaviour {
     public Vector3 realPos;
     public Vector3 tempPos;
     
     // Update is called once per frame
     void Update () {
         if(transform.position != realPos) {
             transform.position = Vector3.Lerp (transform.position, realPos, 0.3f);
         }
 
         if(Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began) {
             Vector3 fingerPos = Input.GetTouch(0).position;
 
             tempPos = fingerPos;
             tempPos.z = 0;
             realPos = Camera.main.ScreenToWorldPoint(tempPos);
             realPos.z = 0;
             Debug.Log (tempPos);
         }
     }
 }