EV, short for Exposure Value, can be defined as the various combinations of camera shutter speed and relative aperture that give the same exposure. For example, 1/30th at f/8.0 is the same EV as 1/60th at f/5.6, and so on. So, if we have a scene with a dynamic range of between 5 and 6 EV our cameras can record detail in both the highlights and shadows areas of the scene. Beyond 6 EV and we must sacrifice details in one extreme or the other.
If we think back to our first example – the shot of the tower and the pier – we can calculate that we would need a camera with a dynamic range of 11 stops to capture the entire dynamic range of the scene (assuming that the native range of our camera is around 6 EV). This is because our overexposed image was +2 EV from the original exposure and the underexposed frame was shot at -3 EV.
