There's no correlation as such, ev is relative to the cameras metered exposure, whereas f-stops are absolute values. Setting ev +1 is one stop more exposure - equivalent to going to a one stop wider f-stop or going for one stop slower shutter. ev -1 is one stop less exposure and so on. Depending on which digital camera you have, you may be able to change from auto/program mode where the camera is deciding shutter/aperture for you to an aperture priority mode (av) where you can set the f-stop yourself. -- Mark

Mark