Exposure- is the amount of light the camera receives on a photosensitive surface.
Aperture- make the picture come out either sharp or grainy and it is also the amount of light that the camera intakes or is exposed to. F stops are the lens focal length, the larger the F stop the more the camera will only focus on one item and blur out the rest, creating a shallow depth of field. The lower the F stop is, the more focused the picture will come out, creating a great depth of field.
Shutter speed- is how long the camera keeps the lens open for the picture, which determines how much light the camera is exposed to. The faster the shutter speed is, the more still a moving object will appear in the photo.
ISO-The exposure meter tells one if the image is revealed to too much or too little light. A high ISO causes the picture to come out grainy, so its best to avoid using it.