What does the ISO setting control in photography?

In photography, the ISO setting primarily controls the light sensitivity of the camera's image sensor. Increasing the ISO value allows the sensor to capture more light, making it particularly useful in low-light conditions or when a faster shutter speed is needed to prevent motion blur. Conversely, a lower ISO setting reduces the sensor's sensitivity, producing cleaner images with less noise in well-lit situations. This ability to adjust the ISO is crucial for photographers who wish to achieve the right exposure while maintaining the quality of their images in varying lighting conditions.

The other options do not accurately describe the function of the ISO setting. While image resolution refers to the pixel dimensions of an image, color saturation pertains to the intensity of colors, and flash intensity deals with the output power of the camera's flash unit. Each of these elements plays a role in photography but is distinct from the impact that ISO has on light sensitivity.