What Is an Iris Diaphragm?
An iris diaphragm is a mechanical device specifically designed to regulate the amount of light passing through it. This makes it a crucial component in various optical instruments.
Commonly found in devices like camera lenses, microscopes, and telescopes, an iris diaphragm consists of a series of overlapping thin metal or plastic plates. These plates form a circular or polygonal shape that can expand or contract to adjust the aperture size – the opening through which light passes. By controlling the aperture size, the iris diaphragm effectively manages the brightness and depth of field in the image or observation.
This process, known as adjusting the variable aperture, directly influences the light transmission. A larger aperture size allows more light to enter, resulting in a brighter image. Conversely, reducing the aperture size limits light entry, leading to a darker image but increasing the depth of field.