Focus In On Object With Camera During Gameplay

Unity3D: How To Focus In On Object With Camera During Gameplay.and I need the camera to jump from one target to another.
ex:i need if i press on a specific key in the keyboard the camera zooms in a specific object in my scene and if i press on another key the camera jump from first object to another .

@ayaelsayed You need to change target of your camera when pressing any key. Write events of keyboard buttons press then write function which changes target of camera at runtime. After doing this you can easily change camera focus on pressing buttons of keyboard.

@abdullahsyyd i did the part of the multiple targets , that the camera transfer from one object to another but the camera fall when it jumps from one object to another.