| 发明名称 |
ZOOM LENS SYSTEM |
| 摘要 |
A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, each of the first through fourth lens groups move along the optical axis thereof. The following conditions (1) and (2) are satisfied:;1.05<ft/f1<1.75 (1), and;3.7<M3t/M3w<6.3 (2),;wherein f1 designates the focal length of the first lens group, ft designates the focal length of the entire zoom lens system at the long focal length extremity, and M3t and M3w designate the lateral magnifications of the third lens group when focusing on an object at infinity at the long and short focal length extremities, respectively. |
| 申请公布号 |
US2016231544(A1) |
申请公布日期 |
2016.08.11 |
| 申请号 |
US201615010432 |
申请日期 |
2016.01.29 |
| 申请人 |
HOYA CORPORATION |
发明人 |
HAYAKAWA Koichiro;KOREEDA Daisuke |
| 分类号 |
G02B15/16;G02B27/00;G02B15/20 |
主分类号 |
G02B15/16 |
| 代理机构 |
|
代理人 |
|
| 主权项 |
1. A zoom lens system comprising a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group, in that order from the object side,
wherein upon zooming from the short focal length extremity to the long focal length extremity, each of said first through fourth lens groups move along the optical axis thereof, and wherein the following conditions (1) and (2) are satisfied:
1.05<ft/f1<1.75 (1), and3.7<M3t/M3w<6.3 (2), wherein f1 designates the focal length of said first lens group, ft designates the focal length of the entire zoom lens system at the long focal length extremity, M3t designates the lateral magnification of said third lens group when focusing on an object at infinity at the long focal length extremity, and M3w designates the lateral magnification of said third lens group when focusing on an object at infinity at the short focal length extremity. |
| 地址 |
Tokyo JP |
