| 摘要 |
PURPOSE:To enable automatic focus to be accurately and rapidly performed and enable the detector to be adapted to any high magnification zoom lenses by providing electrical focus detecting means in the zoom lens system of a camera having zoom mechanism. CONSTITUTION:Respectively first small lens 5 and second small lens 6 are disposed in vertically symmetrical positions with an optical axis 4 in-between, between the variable power system 1 and imaging system 2 of the zoom lens. Sensors 7 and 8 composed of CCDs, BBDs, etc. are disposed on the imaging planes of these small lenses 5 and 6. The light images of the object formed on these sensors 7 and 8 converted to electric signals and the output signals from the sensors 7 and 8 are operated, whereby the signal having the polarity and amplitude corresponding to the deviation of focus is obtained. By controlling the variable power system 1 based on the signal obtained in this way, the focus may be matched automatically, accurately and rapidly. |
