1)In manual mode, the manual says:"when the shutter button pressed half way down, the distance at which the proper exposure is obtained appears on the LCD panel. Now what does the following mean? " Set the aperture to match the displayed distance to the shooting distance." To adjust what aperture? On the camera? 2) "The power level range eg. 1/1 -1/2 corresponds to the aperture range, f4-5.6" What does that mean?