3rd person controller camera passing through walls

Is there a way to stop the camera from passing through objects. I do not want mouse orbit or the "wow control" system as the game will not be played with a mouse only 4 arrow buttons.

I have tried placing a sphere collider on the camera but this collider is ignoring the walls too.

I have also tried placing a child sphere on the camera and have the camera stick on the sphere as it does not pass through the walls. This made the controls freak out.

I have tried to use a Spherecast to detect objects with a tag = "walls" and to then move the camera towards the player in the Z axis....It would be preferable for the player to get a close up off the characters ass instead of the void outside the game.

Any advice you guys may have would be appreciated.

Thanks