Camera Tracking

Hellp I am trying to make a 3d crush the castle/angry birds type game and I need the camera to follow the cannon ball after it is fired then return to the cannon to ready the next shot.

right now I have a working code for firing cannon balls from the camera at the cannon, but I have no Idea how to get the camera to "latch on" to the flying cannonball after shooting. I want a 3rd person view of the cannon ball where I can orbit around the cannon ball.

So here is my to do list

1. figure out how to make the camera follow the cannon ball after shooting

2. add orbiting camera function to the following camera.

I am new to c# scripting and Unity but after many tutorials and trial and errors I at least can fire cannonballs from my cannon.