Zooms lens system and electronic image pickup apparatus using the same
US7515354B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 2007 |
| Grant date | Apr 7, 2009 |
| Priority date | — |
| Expiry date | Nov 14, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens system includes, in order from an object side, a first lens unit G1 having a positive refracting power, a second lens unit G2 having a negative refracting power, a third lens unit G3 having a positive refracting power, and a fourth lens unit G4 having a positive refracting power, and at the time of zooming from a wide angle end to a telephoto end, a space between the lens units changes, and the first lens unit includes two lenses namely, a negative lens and a positive lens, and satisfies the following conditional expression−0.75<SF1p<−0.1 (1)where,SF1p is defined as SF1p=(R1pf+R1pr)/(R1pf−R1pr), whenR1pf is a paraxial radius of curvature of a surface on the object side, of the positive lens in the first lens unit, andR1pr is a paraxial radius of curvature of a surface on an image side, of the positive lens in the first lens unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.