| 摘要 |
PURPOSE:To adjust a focus smoothly and rapidly by varying a space between an objective lens mounting part and a camera body mounting part and moving a junction optical system to an optimum position in accordance with an objective lens. CONSTITUTION:A small reference objective lens 2 having 40 deg. or more picture angle is mounted to a rear conversion lens 1 holding the junction optical system. At the time of focusing on an infinite object, the space L100 between the objective lens mounting part 3 and the camera body mounting part 4 is minimized, and in case of an adjacent object, the space is expanded. Since the small-sized lens 2 is used, both extension and focus adjustment can be easily attained. To focus a large lens 2 having 20 deg. or less picture angle, the interval L100 is kept as it is for an adjacent object and the lens 1 is moved to the body 5 side. Since the interval between the mounting parts 3, 4 is variable and the junction optical system is moved to the optimum position in accordance with the size of the objective lens 2, the focus can be adjusted smoothly and rapidly. |
