If you are using a Samsung phone, open the camera, get it close to the bud as you were trying to autofocus it, then tap and hold the screen until you see a yellow circle with AE/AF Lock written. This will lock your focus, so it does not autofocus anymore so you can do it manually by bringing the camera closer or further away from the bud/picture object.
Hope this helps
Thanks Kay, I have an iPhone so easy enough to do a search and see if it’s possible on that as well. Cheers