Zooming in the camera app while running voiceover

Hello,
I am a voiceover user, but I do have some usable vision. I would like to try to use the camera more, but I'm having some trouble using it with voiceover. I've read that the zoom option in the voiceover rotor is supposed to be to zoom the camera, but it isn't working for me. It does nothing when I flick up or down. Am I doing something wrong? If this isn't how your supposed too zoom the camera with voiceover, can someone please tell me how to do it? I love the information voiceover gives you about positioning of faces ect, so I'd really like to be able to use voiceover and the camera together.
Thanks