| 摘要 |
<p>First light-amount adjustment blades (6, 9) and second light-amount adjustment blades (4, 5, 7, 8) are made to overlap each other annularly, forming an aperture through which light passes. The first light-amount adjustment blades (6, 9) move in a direction that intersects the direction in which light passes through the aperture, and the second light-amount adjustment blades (4, 5, 7, 8) rotate within a plane that intersects the direction in which light passes through the aperture. As the aperture is increased in size, the polygonal shape thereof approaches a circle. A diaphragm aperture is formed by arranging rotating aperture blades (4, 5, 7, 8) between linear aperture blades (6, 9). Rotation of the rotating aperture blades (4, 5, 7, 8) relative to the linear aperture blades (6, 9), which move linearly and are arranged so as to face each other, changes the shape of the diaphragm aperture.</p> |
