| 摘要 |
PURPOSE:To compact a zoom lens of high variable magnification having an about 5 zooming ratio by composing the lens system of five positive, negative, positive, and positive groups, and moving all groups in zooming. CONSTITUTION:The lens system consists of the five positive, negative, positive, negative, and positive groups from an object side, and the variable magnification is varied by moving all the groups so that the air gaps between the 2nd and the 3rd groups, and the 4th and the 5th groups are larger and larger as the focus length is longer and longer and the air gaps between the 2nd and the 3rd, and the 4th and the 5th groups are smaller and smaller as the focal length is longer and longer. Then, conditional equations (1)-(4) hold. Then, fW is the shortest focal length of the whole system, and f12W is the synthetic focal length of the 1st and the 2nd groups with the shortest focal length; and fi is the focal length of the (i)th group, Tij is the air gap between the (i)th and the (j)th groups, and M is its maximum value. |
