camera zoom in and out unity code example

Example 1: camera zooming in unity

using UnityEngine;
 using System.Collections;
 
 public class MouseWheelZoom : MonoBehaviour {
 
     float curZoomPos, zoomTo; // curZoomPos will be the value
     float zoomFrom = 20f; //Midway point between nearest and farthest zoom values (a "starting position")
     
     
     void Update ()
     {
         // Attaches the float y to scrollwheel up or down
         float y = Input.mouseScrollDelta.y;
         
         // If the wheel goes up it, decrement 5 from "zoomTo"
         if (y >= 1)
         {
             zoomTo -= 5f;
             Debug.Log ("Zoomed In");
         }
         
         // If the wheel goes down, increment 5 to "zoomTo"
         else if (y >= -1) {
             zoomTo += 5f;
             Debug.Log ("Zoomed Out");
         }
         
         // creates a value to raise and lower the camera's field of view
         curZoomPos =  zoomFrom + zoomTo;
         
         curZoomPos = Mathf.Clamp (curZoomPos, 5f, 35f);
         
         // Stops "zoomTo" value at the nearest and farthest zoom value you desire
         zoomTo = Mathf.Clamp (zoomTo, -15f, 30f);
         
         // Makes the actual change to Field Of View
         Camera.main.fieldOfView = curZoomPos;
 }

Example 2: camera pinch zoom unity

//I SUGGEST YOU WATCH THE VIDEO ON HOW IT WORKS
//https://www.youtube.com/watch?v=0G4vcH9N0gc&t=127s

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

public class PanZoom : MonoBehaviour {
    Vector3 touchStart;
    public float zoomOutMin = 1;
    public float zoomOutMax = 8;
	
	// Update is called once per frame
	void Update () {
        if(Input.GetMouseButtonDown(0)){
            touchStart = Camera.main.ScreenToWorldPoint(Input.mousePosition);
        }
        if(Input.touchCount == 2){
            Touch touchZero = Input.GetTouch(0);
            Touch touchOne = Input.GetTouch(1);

            Vector2 touchZeroPrevPos = touchZero.position - touchZero.deltaPosition;
            Vector2 touchOnePrevPos = touchOne.position - touchOne.deltaPosition;

            float prevMagnitude = (touchZeroPrevPos - touchOnePrevPos).magnitude;
            float currentMagnitude = (touchZero.position - touchOne.position).magnitude;

            float difference = currentMagnitude - prevMagnitude;

            zoom(difference * 0.01f);
        }else if(Input.GetMouseButton(0)){
            Vector3 direction = touchStart - Camera.main.ScreenToWorldPoint(Input.mousePosition);
            Camera.main.transform.position += direction;
        }
        zoom(Input.GetAxis("Mouse ScrollWheel"));
	}

    void zoom(float increment){
        Camera.main.orthographicSize = Mathf.Clamp(Camera.main.orthographicSize - increment, zoomOutMin, zoomOutMax);
    }
}