Canon EOS-1Ds Mark III EOS-1Ds Mark III Instruction Manual - Page 97

f: Aperture-Priority AE If the "30"" shutter speed blinks, it indicates underexposure. Turn the dial to set a larger aperture (smaller f/number) until the blinking stops or set a higher ISO speed. If the "8000" shutter speed blinks, it indicates overexposure. Turn the dial to set a smaller aperture (larger f/number) until the blinking stops or set a lower ISO speed. Aperture Display The larger the f/number, the smaller the aperture opening will be. The aperture values displayed will differ depending on the lens. If no lens is attached to the camera, "00" will be displayed for the aperture value. Depth-of-Field Preview Press the depth-of-field preview button to stop down to the current aperture setting. You can check the depth of field (range of acceptable focus) through the viewfinder. A higher f/number will make more of the foreground and background fall within acceptable focus. However, the viewfinder will look darker. If the depth of field is difficult to discern, hold down the depth-of-field preview button while turning the dial. The exposure will be locked (AE lock) while the depth-of-field preview button is pressed. 97