Zooming Optical System, Imaging Optical Device, And Digital Device
AssigneeKonica Minolta, Inc.
InventorYoshihito Souma
Life of this patent
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Abstract
A zooming optical system has, from the object side, a positive first group, a negative second group, a positive third group, a positive fourth group, and a negative fifth group. During zooming, at least the third to fifth groups move relative to the image plane, and focusing is achieved by moving the fourth group along the optical axis. The conditional formula −1.0<M5/f5<−0.1 is fulfilled, where M5 is the distance along the optical axis from the position of the fifth group at the wide-angle end to the position of the fifth group at the telephoto end and f5 is the focal length of the fifth group.
Claims20
A zooming optical system comprising, from an object side, a first group having a positive optical power, a second group having a negative optical power, a third group having a positive optical power, a fourth group having a positive optical power, and a fifth group having a negative optical power, the zooming optical system achieving zooming by varying axial distances between the individual groups, wherein
- during zooming, at least the third, fourth, and fifth groups move relative to an image plane,
- focusing is achieved by moving the fourth group along an optical axis, and
- conditional formula (1) below is fulfilled:
- −1.0<M5/f5<−0.1 (1)
- where
- M5 represents a distance along the optical axis from a position of the fifth group at a wide-angle end to a position of the fifth group at a telephoto end;
- and
- f5 represents a focal length of the fifth group.
Dependencies are inferred from the claim text.