Why is auto ISO not available in the M mode? There are times when I want to manually set the shutter speed and the aperture but want the camera to pick the best ISO for appropriate exposure. But my GF1's M mode does not provide auto ISO. Any reason for that? I hate to compare with my LX3, but my LX3 made shooting in the M mode easier by providing auto ISO. Thus, allgorithm-wise, Panasonic could have easily built auto ISO into the M mode.