| 摘要 |
PURPOSE:To enable the immediate identification of the focal length of a lens system in the stage of photographing with a simple mechanism, by the constitution wherein whether another lens unit inserted on the same optical axis in the lens system is held in the optical axis or is deviated therefrom is detected. CONSTITUTION:A lens L6 constituting a built-in extender is contained in a rotating body 34, and the built-in extender is put into or out from the optical axis by the operation of a handle 37. A ring 27 is fitted onto the cavity part of a zoom operating ring 15, and a detection bar is provided in parallel with the optical axis. When the built-in extender is within the optical axis, the ring 27 is slided to the left side by the detection bar and indicates the figure on the ring row of a scale plate 30 indicating the focal lengths engraved in two rows. When the extender deviates from the optical axis, the figure on the left row of the plate 30 is indicated. Thus, the required focal length is displayed immediately with the simple mechanism according to the using condition of the built-in extender. |
