What camera component resembles the iris and controls light entering the camera?

• A. Shutter
• B. Aperture
• C. ISO
• D. Lens

Answer: (B)

Adjusting the size of the opening through which light enters the camera is the main concept. This opening is the aperture, and it behaves like the iris in your eye—open wider to let in more light, or close down to limit it. Aperture is described by f-stops; a small f-number means a larger opening, which brightens the image and creates a shallower depth of field. A large f-number reduces light and increases depth of field. The aperture is one part of the exposure triangle, working alongside shutter speed (how long the sensor is exposed) and ISO (sensor sensitivity). The shutter controls how long light reaches the sensor, ISO determines how sensitive the sensor is to light, and the lens is the optical element that focuses light onto the sensor. In practice, choosing the aperture lets you control brightness and depth of field, while adjusting shutter speed and ISO balances exposure.