Changes in lighting can confuse even the best automatic cameras, which is why the Nikon D80's ISO setting comes in handy. This setting corresponds with the speed of film used in traditional photography and changes how sensitive the digital photo sensor is to light. When you can't or don't want to use flash, such as in an indoor arena or show, a high ISO makes the sensor more sensitive to light. Manually changing the ISO on the D80 is simple, an advantage that allows you to compensate for the light without having to compromise speed or potentially miss important moments.
Put the Nikon D80 in manual or semi-automatic mode because the automatic mode on the Nikon D80 contains preset ISO instructions that cannot be altered.
Press and hold the checkerboard/magnifying glass button on the back of the camera. This button is marked "ISO."
Turn the thumb dial located on the back of the camera to change the ISO. The D80 has ISO settings ranging from a low 100 to super sensitive 3200. Monitor your changes using the camera's LCD screen.
Look through the lens and view the in-camera light meter reading. The changed ISO will affect your meter reading -- when the meter gauge is balanced in the center, your exposure settings, including ISO, are correct for the light entering the lens.