Aperture
The aperture is a ring inside of the lens which is used to measure how much light enters and hits the sensor to make the image bright or dark. Aperture goes by a thing called F stop, F Stop is just a name to show the measurement of how much light is going through the camera. F/2 – F/4.5 is used mainly for portrait photos as it creates a shallow focus and has a small depth of field. With F/8 or higher the blur is much less and these F stops are used mostly for landscape photos.
Shutter Speed
Shutter speed is how long the shutter covering the sensor for is open for. Having a fast shutter speed causes things to stay in place like an arm moving or a waterfall, however with a slow shutter speed things become blurred that move.
ISO
ISO is used to add more light into your shot or darken it. ISO 100 is the darkest ISO and also creates no noise however, once you reach 400 ISO – 800 ISO the noise/grain becomes more prominent.