Originally Posted by
Gorilla
. . . Aperture priority works well in many situations, and after mastering the the EC control, at times it is often all you need. However, Manual mode is far more flexible. Say your shooting a reception in relatively low light. In Aperture priority, you may try to bump up the exposure value by adding, say, +1 EC. But the camera hass already calculated a relatively slow shutter speed (let's say 1/60th second). In Aperture priority, if you add +1 EC you are telling the camera to use a shutter speed of 1/30th - and now you have significant risk of unacceptable blur in the shot. In Manaul mode, you can keep your shutter speed acceptable, open your Aperture, adjust your ISO (and of course, use a flash!)