| 摘要 |
PURPOSE:To perform sure operation by providing such a regulating means by which the movable range of a lens group is made to the focusing distance at the focal length of that time cooperatively with zoom operation. CONSTITUTION:By zoom operation, a lens group 1 is moved forward and backward along a cam groove 6, a lens group 3 along a cam groove 8 and a lens group 2 along a cam groove 7, whereby correction operation is accomplished. A lens group 4 is a lens grOup which is moved for the purpose of focusing, and the position with respect to an object distance infinity is not moved by the zoom operation. The movable range of the lens group 4 is regulated by a member 12, and this member 12 and the cam grooves 6, 7, 8 are set in one lens-barrel. The regulating member 12 forms a narrow aperture 11 on the wide side and a wide one on the telephoto side, and the edge 10 on the right side thereof is aligned to the infinity position of the lens group 4. The edge 9 on the left side is aligned to the position of the lens group 4 with respect to the closest object distance. Pins are erected on the side faces of the frames of the respective lens groups 1-4, and pass through the respectively corresponding cam grooves 6, 7, 8 and the aperture 11. These pins engage with the linear grooves in the forward and backward directions on the inside surface of the zoom operating ring on the outer side of the lens-barrel. |
