How do I turn on the camera?
Solution 1:
There should be a switch labeled "AR" in the top right corner of the screen when catching Pokemon. Turn that switch on to use the camera.
Solution 2:
To enable the AR option to use the camera, go to:Home > Settings App > Pokemon Go (usually at the bottom) and slide the switch tagged Camera from grey to green, close Pokemon GO from recently opened apps and open Pokemon GO back up.