Zoom lens and video camera comprising the same
US5940221A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1996 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | Feb 20, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A compact zoom lens comprising a small number of lenses, providing an aperture of about F1.4 and a zoom ration of about 14, with a full angle of view at the wide angle end of 64.degree. or wider. The zoom lens of the present invention comprises, aligned respectively from the object side, a fixed first lens group, comprising a lens with a negative refracting power, a lens with a positive refracting power, and a meniscus lens with a positive refracting power; a movable second lens group to provide zooming effect, comprising a lens with a negative refracting power, a biconcave lens with a negative refracting power, and a lens with a positive refracting power, with at least one surface of these lenses aspheric; a fixed third lens group with a positive refracting power, with at least one surface of these lenses aspheric; a fourth lens group, movable for compensating the position of the focal plane, with a positive refracting power, with at least one surface of the lenses aspheric. The below mentioned formula (1) is satisfied, EQU 0.1<(fw.multidot.tan W)/(f1.multidot..vertline.f2.vertline.).sup.1/2 <0.35(1) where fw is a focal length of the zoom lens operating in a wide angle condition, …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.