My understanding is that f-stop and aperture aren't the same thing, but the are related. The f-stop being a ratio between the focal length and the actual size of the aperture. The actual physical size of the aperture on a F2.8 24mm lens is actually smaller than a F2.8 200mm lens, even though the F-stop value is the same, and the way I understand it, more or less the same amount of actual light reaches the sensor in both lenses at the same F-stop even though the physical aperture on the 200mm is much larger. So with a small point and shoot camera, the same amount of light hits the sensor per square inch of sensor, but the point and shoot sensor has a much smaller size, and therefor a much less light per pixel.... I think...