| 摘要 |
PURPOSE:To execute focusing by a simple structure by setting a master lens to a fixed focus at the time of a wide angle photographing, and moving it in the optical axis direction by inserting a conversion lens into its rear at the time of a telephoto photographing. CONSTITUTION:At the time of a wide angle photographing, a conversion lens 15 is saved from an optical axis 3, and a master lens 2 is not moved so that a distinct picture is obtained by only the depth of field. At the time of a telephoto photographing, the lens 15 is inserted onto the optical axis 3 by turning a switching ring 10 and rotating a lens holder 14 by a cam 12, and when a cam plate 20 rotates in accordance with a distance zone, a rod 16 is moved by its tapered part 20a, therefore, simultaneously, the lens 14 also moves along the optical axis 3, and focusing is executed. Accordingly, a focusing mechanism of the master lens 2 and a focusing rod become unnecessary, a constitution of a shutter device is simplified, and an interlocking mechanism with a distance measuring device at the time of a telephoto photographing can be made extremely simple. |
