Zoom lens and imaging apparatus
US8000024B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 2, 2009 |
| Grant date | Aug 16, 2011 |
| Priority date | — |
| Expiry date | Dec 2, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens is provided and includes: a first lens group having a positive power, a second lens group having a negative power, a stop, a third lens group having a positive power, and a fourth lens group having a positive power in order. Zooming is performed by moving at least the first lens group, the second lens group, the stop, and the third lens group along the optical axis. During zooming, the stop is moved so as to be closer to an image plane at a wide-angle end than at a telephoto end and to be closer to the second lens group at the telephoto end than at the wide-angle end. The following conditional expressions (1) and (2) are satisfied. For the conditional expressions (1) and (2), fw is a focal length at the wide-angle end of the entire system, ft is a focal length at the telephoto end of the entire system, f1 is a composite focal length of the first lens group, and X1 is a displacement of the first lens group during zooming from the wide-angle end to the telephoto end.4.0<f1/fw<7.0 (1)0.2<X1/ft<0.3 (2)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.