Can anyone show me how to use Sphere casting on a Camera to detect collisions and redirect the camera accordingly? I want to use this as an alternative to a collider on a camera since it loses it's position on collision.

The camera is following from a third person perspective, I just need the camera to maneuver out of the way of the obstacle. Like rotating around the player by 90 degrees or moving closer if it meets with a wall. The camera controller is based off the tutorial I found but it was never completed by Unity labs.

http://www.unitylabs.net/tutorials/gameplay-mechanics/third-person-camera-controller