| 摘要 |
PURPOSE:To perform excellent focusing at low cost with simple constitution by driving and moving a master lens group by using a pulse motor and a lead screw. CONSTITUTION:A camera wherein a front lens group is fixed and a master lens 5 is moved is so structured that a ball bearing 25 does not comes out by a retainer 26 by providing the ball bearing 25 in the gap between the internal cylinder 24 and external cylinder 27 of the master lens. Then the internal cylinder 24 is coupled with a moving frame 28 by a coupling mechanism 30 and engaged with the shaft 10 composed of the lead screw. In this constitution, the master lens 5 is sufficiently lightweight, so the low-torque pulse motor 9 is used to vibrate the master lens 5 through the lead screw and move it, thereby performing the excellent focusing. |
