In photography, the diaphragm is the mechanical component inside a camera lens that controls the aperture, regulating the amount of light that reaches the film or digital sensor. It is typically made from a series of overlapping blades that open and close to adjust the size of the aperture.
The diaphragm not only affects exposure but also influences depth of field-the range of the image that appears sharp. A wider aperture (blades more open) allows more light in and creates a shallow depth of field, while a smaller aperture (blades more closed) reduces light and increases depth of field. Understanding the diaphragm is essential for photographers seeking precise control over exposure, focus, and artistic effects like background blur (bokeh).