Unity C# 3D Zoom Camera Depending How Far Is Object

C# script to zoom in and out camera, depending how far from camera is object.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

// ? 2017 TheFlyingKeyboard and released under MIT License
// theflyingkeyboard.net

public class FollowAndZoom : MonoBehaviour {

    [SerializeField] private Transform target;
    [SerializeField] private float minSize;
    [SerializeField] private float maxSize;

    void Update()
    {
        transform.LookAt(target);

        Camera.main.fov = Mathf.Clamp(maxSize - (target.position - transform.position).magnitude, minSize, maxSize);
    }
}