Making the camera not go under 0 in height

Colliders are coming soon to Unity cameras @Traczy !

Check this out https://vimeo.com/182876861 the collider specific section starts at 1:30.

An upcoming version of Unity will have: Free-Look - 3rd person AA camera control Collider - Keep your cameras from getting tangled with objects Cloud - Always cut to a camera with a good shot Reactor - The ultimate driving / follow camera system

I know this doesn't help you today... but it will be available early in the new year.

Attach a script to the camera like this

 void LateUpdate()
 {
    if (gameObject.transform.position.y = < 0)
       gameObject.transform.position.y = 0;
 }
 

EDIT: Thanks for pointing that out, LateUpdate is much more appropriate. Also you could easily incorporate panning and such into the script. Now this is a bit of a trick, but... depending on your game, you could add a Collider to the camera :P