I am trying to understand some aspects of aperture and how it relates to the sensor. When the aperture is wide open, I can visualize that the sensor is fully covered in light. As the aperture is stopped down, however, I am picturing that the light coming through covers less of the sensor. I am guessing that it does not happen that way, because you'd have a big area of dark/shadow on the sensor. In my head, I am picturing the aperture stopped down is something similar to a pinhole in a sheet of paper. Hold the paper up in front of a wall, shine a light through it, and you'll see just a small light dot on the wall. On that same sheet of paper, cut hole the size of a nickel. Hold the paper the same distance from a wall as before, then shine a light through that, and you'll see a much larger area of light on the wall. What am I missing? What enables the sensor to 'see' the entire picture as the aperture is stopped down?