Tekken Fighting game Camera

Hi, I'm working on this 3d fighting game, it's almost a tekken clone. Now I need to code the camera movement. I already have the code for the camera movement, it always lookAt the side of two characters. But my problem is I can't make it zoom Out/in as the player moves away from each other. I tried a lot of solution found in the internet but nothing solves it or related to it. Players move SSBB like in tekken, all scripts I found was for game whose characters are only moving on X-axis. Here's my code:

 using UnityEngine;
 using System.Collections;
 
 public class CameraMovement : MonoBehaviour {
     Transform player1;
     Transform player2;
     Transform mTransform;
     Transform mCenterTrans;
     public GameObject centerPoint;
     public Vector3 cameraOffset;
     public float height;
 
     float marginx = 3f;
 
     Vector3 center;
     Vector3 offset;
     void Start () {
         mCenterTrans = centerPoint.transform;
         mTransform = transform;
         player1 = Player.player1.mCharacter.mModel.transform;
         player2 = Player.player2.mCharacter.mModel.transform;
         centerPoint.transform.position = centerOfChars(player1.position,player2.position);
         offset = centerPoint.transform.position - transform.position;
     }
 
 
     void LateUpdate () {
         updatePosition ();
     }
 
     void updatePosition()
     {
         //calculate distance of players
         float distanceOfCharacters = Vector3.Distance (player1.position, player2.position);
 
         //update centerPoint position
         mCenterTrans.position = centerOfChars(player1.position,player2.position);
         mCenterTrans.LookAt (player2.position);
 
         //calculate for nexPosition of Camera
         float angle = (mCenterTrans.eulerAngles.y);
         float anglez = (mCenterTrans.eulerAngles.z);
         Quaternion rotation = Quaternion.Euler (0, angle,0);
         mTransform.position = mCenterTrans.position - (rotation * offset);
         center = mCenterTrans.position;
 
         //add height to camera
         center.y += height;
         mTransform.LookAt (center);
     }
 
     Vector3 centerOfChars(Vector3 pCharPos1,Vector3 pCharPos2)
     {
         return (player1.position + player2.position) * 0.5f;
     }
 }
 

Any help if you can?