Birch, Stewart, Kolasch & Birch, LLP
Lens barrel
The present invention provides a lens barrel having an optical system capable of change of a focal length, comprising: a diaphragm device which controls a light amount of light incident to the optical system and passing to an image forming surface; and an open F value varying device which is provided separately from the diaphragm device, controls a light amount of the light incident to the optical system and passing to the image forming surface and varies an open F value by limiting the light amount so that the open F value becomes a value according to a focal length of the optical system when the light amount which is controllable by the diaphragm device is at the maximum.
Fujinon Corporation
G G
G02B G03B
inventional inventional
Toshiaki Yoshitaka
Takeda Mori