If you double the ISO setting from the default, by how many stops does exposure change?

• A. Half stop
• B. One stop
• C. Two stops
• D. No change

Answer: (B)

Stops measure how much light the sensor receives. Doubling the ISO increases the sensor’s sensitivity by a factor of two, which is one stop of exposure. So, with the same shutter speed and aperture, raising ISO from the default makes the image brighter by one stop. The other options describe halves, quadruples, or no change in exposure, which don’t align with how ISO affects brightness. If you needed to keep the exposure the same after doubling ISO, you’d compensate by lowering the shutter speed or stopping down the aperture by one stop.