What does a camera's ISO setting affect?

The ISO setting of a camera primarily affects the sensitivity of the camera's sensor to light. A higher ISO value means the sensor is more sensitive, allowing it to capture images in lower light conditions without the need for longer exposure times. Conversely, a lower ISO indicates lower sensitivity, which is ideal for shooting in bright lighting conditions, helping to prevent overexposure.

The other options are impacted by different settings: shutter speed controls the duration that light hits the sensor and can affect motion capture; depth of field relates to the aperture setting and determines how much of the scene is in focus; and white balance is responsible for correcting colors based on the light source. Thus, while all these factors play essential roles in photography, only the ISO setting is directly related to the camera's sensitivity to light.