| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable exact automatic focusing even when a manual focusing moving cam is used by specifying the ratio of the micro-moving quantity of an imaging plane to the micro-moving quantity of the focusing lens group at infinity focusing point and the closest focusing point and the moving quantities of the focusing lens group required for focusing from infinity to the closest distance at a wide angle end and telephoto end. SOLUTION: The ratio dBf/dx of the micro-moving quantity dBf of the imaging plane to the micro-moving quantity dx in the optical axis direction of the focusing lens group at the infinite focusing point and the closest focusing point is defined asγXO,γXR, respectively. The moving quantity in the optical axis direction of the focusing lens group required for focusing from the infinity to the closed distance at the wide angle and the telephoto end is defined asΔXWR,ΔXTR, respectfully. The rotating quantity corresponding to the variable magnification from the wide angle to telephoto of the moving cam for focusing and the rotating quantity corresponding to the closest focusing state from the infinite focusing state are defined as aZ, aP, respectively. At this time, the equations 0.60<γXR/γXO<1.70, 0.50<ΔXTR/ΔXWR<2.00, 0.30<|aF/aZ|<2.50.</p> |
