You will very often hear photographers talking about exposure, in many different terms. I'm sure you can think of more than a couple, but the popular ones are, "That was a nice exposure", "That was a little under exposed", "That was over exposed", or even "You may want to try a longer/shorter exposure". But what are people actually saying?
So, lets first look at the word "exposure". This term is exactly as it sounds, it is how much light we are exposing our digital sensor or film to. As photographers, we are striving to master the art of the manipulation of light, we are attempting to bend light through our lenses, and focus it onto a single plane in which we place a film or sensor that is sensitive to light. Exposing this focussed image onto this sensor is where we get our image.
Exposure is what we do to create that image, we use the camera to manipulate two (and only two) components in which we adjust our exposure. That is our shutter and our aper