| 摘要 |
PURPOSE:To obtain a very compact zoom lens by arranging the shifting lens group before and after the light path divider and having the lens part to shift accompanying the zooming on the divided light path. CONSTITUTION:Between the foremost lens group, namely, a variable power group 2, and the lattermost lens group, namely, a correcting group 3, a light path dividing prism 4 and a diaphragm are arranged. In such a way, the interval between the foremost lens group and the diaphragm can be shortened and the front lens diameter can be reduced. Next, a lens group 7 for projection and a light source 8 for detecting the focus such as the infrared light emitting diode are successively arranged on the light path divided by a light path dividing prism 4. Since the divided light flux generates the image point shifting, this is compensated by interlocking and shifting to the lens group 7 for projection and the variable power group 2. Thus, the zoom lens equipped with the light path dividing prism can be made very compact including the optical system to detect the automatic focus. |
