Which component of photography controls the amount of light hitting the sensor?

The aperture is a critical component of photography that directly controls the amount of light entering the camera and hitting the sensor. It is defined by the size of the opening in the lens when a photograph is taken. A larger aperture allows more light to pass through, resulting in a brighter image, while a smaller aperture restricts the light, leading to a darker image.

In practical use, the aperture is measured in f-stops, such as f/1.8, f/4, or f/16, with lower numbers indicating wider openings. Not only does the aperture impact exposure, but it also influences depth of field—where a wider aperture creates a shallow depth of field that blurs the background, while smaller apertures increase depth of field, keeping more of the image in focus.

Shutter speed controls how long the sensor is exposed to light, impacting motion blur. ISO determines the sensor's sensitivity to light but does not directly control the light itself. A tripod stabilizes the camera, preventing motion during exposure but does not influence light levels. Therefore, the aperture plays the essential role in regulating light intensity reaching the sensor, making it the correct choice.