Tie It All Together

The best way for a rookie to look at Aperture, ISO, Shutter Speed and Exposure is by imagining a water faucet that only pours out white paint onto a black canvas.

Imagine the white paint as light and to create a beautiful picture on a black canvas, you have to control certain setting to either restrict, increase, focus and/or unfocus the light . 

Shutter speed (Tv) - How long you wish to leave your faucet on.

Aperture(Av) - How wide your faucet's circumference is.

ISO - At what pressure your white paint will shoot out of the faucet tap.

Exposure - Is how much of the black canvas will be painted.