| 发明名称 |
Inner focus lens, interchangeable lens apparatus and camera system |
| 摘要 |
An inner focus lens, in order from an object side to an image side, comprising: a first lens unit having positive optical power; a second lens unit having negative optical power; and a third lens unit having positive optical power, wherein the second lens unit is moved along an optical axis so that focusing from an infinite-distance object side to a short-distance object side is achieved, the first lens unit includes a bi-convex air lens, and the following conditions: 0.65<|f2/f|<5.00 and 0.5<f23/f1<9.0 (f2: a focal length of the second lens unit, f and f23: a focal length of the entire system and a composite focal length of the second and third lens units in an infinity in-focus condition, f1: a focal length of the first lens unit) are satisfied; an interchangeable lens apparatus; and a camera system are provided. |
| 申请公布号 |
US8749893(B2) |
申请公布日期 |
2014.06.10 |
| 申请号 |
US201313935547 |
申请日期 |
2013.07.04 |
| 申请人 |
Panasonic Corporation |
发明人 |
Imaoka Takuya;Hoshi Koji;Hagimori Hitoshi |
| 分类号 |
G02B15/14;G02B3/02 |
主分类号 |
G02B15/14 |
| 代理机构 |
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代理人 |
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| 主权项 |
1. An inner focus lens, in order from an object side to an image side, comprising:
a first lens unit having positive optical power; a second lens unit having negative optical power; and a third lens unit having positive optical power, wherein the second lens unit is moved along an optical axis so that focusing from an infinite-distance object side to a short-distance object side is achieved, the first lens unit includes a bi-convex air lens, and the following conditions (1) and (4) are satisfied:
0.65<|f2/f|<5.00 (1)0.02<D2/{f×tan(ω)}<0.30 (4) where, f2 is a focal length of the second lens unit, f is a focal length of the entire system in an infinity in-focus condition, D2 is an optical axial thickness of the second lens unit, and ω is a half view angle (°) of the entire system in an infinity in-focus condition.
|
| 地址 |
Kadoma-shi JP |
