G lenses don't work fully with F601 cameras. They're not compatiable. For whatever reason, the only modes it works right with are shutter priority and programmed auto. The F601 can't correctly control the aperture in A or M mode. The reason your shots were underexposed is probably that you were setting it to f/5.6 and getting shutter settings from that, but there's no way to know what the "real" f-stop was when you clicked the shutter. Could have been closing all the way down to f28 or f32. Try using it in shutter priority or program auto modes. That way, the camera will set the proper aperture. -=>Donald