| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a diaphragm device that can make a diaphragm opening shape close to circle in a wider range of diameter (size) of a diaphragm opening, and prevent a plurality of diaphragm blades from rising up even when the diameter (size) of the diaphragm opening is reduced; and an optical instrument including the diaphragm device.SOLUTION: A plurality of diaphragm blades have a first diaphragm blade set and a second diaphragm blade set different from each other in the shape of a formation edge of the diaphragm opening. A diaphragm device comprises, in order to change the diameter of the diaphragm opening: a first zone in which the formation edge of the diaphragm opening of the first diaphragm blade set forms the diaphragm opening alone; and a second zone in which the formation edge of the diaphragm opening of the second diaphragm blade set forms the diaphragm opening alone.</p> |
