Does anyone know how to adjust the focal length of Apple's mobile phone?

The method for adjusting the focal length of Apple mobile phone is:

1. Turn on the camera function on the desktop of the mobile phone system;

2. Keep the pages in the picture taken by the camera behind the mobile phone;

3. Select the person or thing to shoot and put it in the middle of the screen;

4. Long press the object you want to shoot on the screen;

After 5 or 2 seconds, a CD with focus adjustment appears on the shooting interface;

6. By adjusting the position of the pointer on the disc, the function of adjusting the focal length of the Apple mobile phone can be realized.