diaphragm

In photography, the diaphragm is a crucial component within a camera lens that controls the amount of light reaching the film or sensor. It functions similarly to the iris in the human eye, using adjustable leaves to change the size of the central opening, known as the aperture. This aperture is measured using f-numbers, where a smaller f-number indicates a larger opening and more light, and a larger f-number signifies a smaller opening and less light.12345

The diaphragm works in conjunction with the camera's shutter, which controls the duration of the exposure. Together, the diaphragm and shutter settings determine the overall photographic exposure, ensuring the image accurately captures the subject's brightness and the film's sensitivity. A diaphragm shutter specifically opens from and closes to the center.126