发明名称 |
Image forming lens system and image pickup apparatus using the same |
摘要 |
An image forming lens system includes an aperture stop, and an image-side lens unit group which is disposed on an image side of the aperture stop. The image-side lens unit group includes a first image-side lens unit having a negative refractive power, a second image-side lens unit having a positive refractive power, and a third image-side lens unit having a negative refractive power. Any one of the first image-side lens unit, the second image side lens unit, and the third image-side lens unit is a focusing lens unit which moves along the optical axis at the time of focusing, and the following conditional expression (1) is satisfied:
0.06<|ffo/f|<0.4 (1)where,f denotes a focal length of the image forming lens system at the time of focusing at an object at infinity, andffo denotes a focal length of the focusing lens unit. |
申请公布号 |
US9297984(B2) |
申请公布日期 |
2016.03.29 |
申请号 |
US201414537163 |
申请日期 |
2014.11.10 |
申请人 |
OLYMPUS CORPORATION |
发明人 |
Kawamura Kazuteru;Fujikura Takashi |
分类号 |
G02B13/02;H04N5/232;G02B27/64;G02B9/00;G02B9/62 |
主分类号 |
G02B13/02 |
代理机构 |
Kenyon & Kenyon LLP |
代理人 |
Kenyon & Kenyon LLP |
主权项 |
1. An image forming lens system comprising:
an aperture stop; and an image-side lens unit group which is disposed on an image side of the aperture stop, wherein the image-side lens unit group includes in order from the aperture stop to the image side along an optical axis, a first image-side lens unit having a negative refractive power, a second image-side lens unit having a positive refractive power, and a third image-side lens unit having a negative refractive power, and any one of the first image-side lens unit, the second image-side lens unit, and the third image-side lens unit is a focusing lens unit which moves along the optical axis at the time of focusing from an object at infinity to an object at a close distance, and the following conditional expression (3) is satisfied:
0.08<fR2/f<0.33 (3) where, fR2 denotes a focal length of the second image-side lens unit, and f denotes a focal length of the image forming lens system at the time of focusing at an object at infinity. |
地址 |
Tokyo JP |