What component of a photographic lens regulates the amount of light passing to the sensor?

The aperture is the component of a photographic lens that regulates the amount of light that passes through to the sensor. It is essentially an opening within the lens that can be adjusted to control light entry, similar to the pupil of an eye. A wider aperture allows more light to enter, resulting in brighter images, while a smaller aperture allows less light, which can create darker images or greater depth of field.

The focal length, while important for determining the magnification and field of view of the image, does not control light intensity. An SD card serves as storage for images captured, and backlight compensation is a feature used in video cameras to address lighting issues in scenes with strong backlighting, but neither of these adjusts the light entering the camera. Understanding the aperture is crucial for mastering exposure, as it directly influences the final image quality and artistic effects.