ISO Speed
This setting adjusts the sensitivity of the camera to light. When ISO Speed is set to the default Auto setting, the camera selects the best ISO speed for the scene.
Lower ISO speeds capture images with the least amount of grain (or noise), but result in slower shutter speeds. If taking a picture in low light conditions without a flash at ISO 100 or below, use a tripod.
Higher ISO numbers allow faster shutter speeds, and can be used when taking pictures in dark areas without a flash, or when taking pictures of fast moving objects. Higher ISO speeds produce pictures with more grain (or noise) and, therefore, can be of lower quality.
1.In the Capture Menu (see page 62), select ISO Speed.
2.Use the 
buttons to highlight a setting.
3.Press 
to save the setting and return to the Capture Menu.
If the new setting is anything other than the default, the icon for the setting will appear in the Live View screen.
The ISO Speed setting remains in effect until it is changed again, or until you turn the camera off. To save changed settings, use My Mode (see page 56).
NOTE: The ISO Speed setting does not apply in Theatre mode nor when recording video clips.