Canon EOS 20D EOS 20D Instruction Manual - Page 79

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 Value 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 PreviewN Press the depth-of-field preview button to stop down to the current aperture setting. The diaphragm in the lens will be set to the current aperture so you can check the depth of field (range of acceptable focus) through the viewfinder. ¡ In the mode, press the shutter button halfway to focus, then press the depth-of-field preview button while still pressing the shutter button halfway. ¡ The exposure is locked (AE lock) while the Depth-of-Field Preview button is pressed. 79