CODE EXAMPLE FOR CSHARP

unity camera follow

public Transform Target; // Drag the object that will be followed in the inspector.
public Transform Camera; // Drag the camera object in the inspector.
Vector3 tempVec3 = new Vector3(); // Temporary vector 3.

void LateUpdate()
{
  	// If the target is active in the scene, set the x camera position to target.
    if (Target != null)
    {
        tempVec3.x = Target.position.x;
        tempVec3.y = this.transform.position.y;
        tempVec3.z = this.transform.position.z;
        this.transform.position = tempVec3;
    }
  	// If target is not active in the scene, set the x camera position to itself.
    else if (Target == null)
    {
        tempVec3.x = Camera.position.x;
        tempVec3.y = Camera.transform.position.y;
        tempVec3.z = Camera.transform.position.z;
        Camera.transform.position = tempVec3;
    }
}