Zoom lens system and electronic image pickup apparatus using the same
US7433132B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 2007 |
| Grant date | Oct 7, 2008 |
| Priority date | — |
| Expiry date | Nov 14, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A four-unit zoom lens system includes in order from an object side, a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a positive refracting power, and a fourth lens unit having a positive refracting power, in which at a time of zooming from a wide angle end to a telephoto end, at least the first lens unit, the second lens unit, and the third lens unit move, and a space between the lens units changes, and a total number of lenses in the second lens unit is not more than three, and the zoom lens system satisfies the following conditional expressions.1.2<(β2t/β2w)/(β3t/β3w)<6.0 and (1A)3.0<ft/fw<20.0 (2A)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.