The shutter controls which aspect of exposure?

• A. The length of time the film will be exposed to light
• B. The focal length
• C. The ISO setting
• D. The color balance

Answer: (A)

Shutter speed is about how long the sensor is exposed to light. When the shutter opens for a set amount of time, light reaches the film or sensor for that duration. A short exposure time means less light hits the sensor, so the image is darker and moving subjects can stay sharp. A long exposure time lets in more light, brightening the image but potentially causing motion blur if objects move. This is separate from aperture (which controls how much light hits per unit time) and ISO (which sets sensor sensitivity). So the shutter controls the length of time the film or sensor is exposed.