Download Third Person Camera FREE Unity. 

Third Person Camera uses advanced features to ease the problems for content creators and players. Be it freeform, auto-following or locking on targets. This asset is the ultimate package to get you started on developing games, not camera systems.

Third Person Camera Features:
– Collision Sensitivity:
Aspherical collision algorithm makes sure the camera doesn’t clip into any geometry.
– Smart Pivot:
Sets a pivot point when the camera is hitting the ground while looking up and prevents the character from blocking the view.
– Thickness Checking:
Thickness checking can be configured to ignore smaller obstacles like sticks, trees, etc… to not reposition or zoom in the camera.
– Over the shoulder:
Out of the box support for games that use additional camera offsets for aiming without changing the rotation pivot of the character or offsetting the aim position.
– Follow mode:
Automatic following of the specified target without the need to manually adjust the camera.
– Follow slope alignment:
Automatically aligns the camera upwards or downwards when the target is on slopes.
– Lock On Mode:
An easy to set up a lock-on mode that keeps the player and your target in focus.
– Controller support

It also has no other script dependencies, is easy to configure and has great extend-ability with it’s clean written C# code.