| 摘要 |
PURPOSE:To enable the continuous macrophotography with simple constitution by extending a straight part in a cam groove for zooming. CONSTITUTION:When a zooming operation part 15 is positioned on a long focus side L, a straight part 11c is extended from said position in a cam groove 11a for zooming, and the groove 8 in the straight chamber engaged with a guide pin 13 and the part 11c are parallel; therefore, if the part 3 is moved in the optical axis direction, the part 3, a sliding cylinder 5 and the pin 13 move integrally in the optical axis direction, thereby setting a macrophotographing state. The pin 13 is held engaged with the parallel groove 8 and the part 11c of the cam groove; therefore, the turning of the cam 10 is prohibited and the focusing in the macro region is accomplished satisifactorily. The macrophotography by which the photographing magifications are continuously increased is thus accomplished with the simple constitution. |
