Zoom lens and image pickup apparatus including same
AssigneeCanon Kabushiki Kaisha
InventorYuichi Gyoda
Life of this patent
Estimating the term…
Abstract
The zoom lens according to the present invention includes, in order from an object side to an image side, a first lens unit with a negative refractive power and a rear lens group including one or more lens units, in which intervals between adjacent ones of the lens units are changed during zooming and focusing. The first lens unit includes three or more negative lenses. The rear lens group includes a focus lens unit with a negative refractive power that moves during focusing. A focal length of the first lens unit, a shortest focal length of the zoom lens, curvature radii of object-side and image-side lens surfaces of a lens in the first lens unit disposed closest to the object side, and a focal length of the focus lens unit are appropriately set.
Claims14
A zoom lens comprising, in order from an object side to an image side, a first lens unit with a negative refractive power and a rear lens group including one or more lens units, intervals between adjacent ones of the lens units being changed during zooming and focusing, wherein
- the first lens unit comprises three or more negative lenses,
- the rear lens group comprises a focus lens unit with a negative refractive power that moves during focusing, and
- the following conditional expressions are satisfied:
- 0.85<|f1|/fW<7.0,
- 0.40<(R1−R2)/(R1+R2)<0.80, and
- 2.0<|fF|/fW<7.0
- where f1 represents a focal length of the first lens unit, fW represents a shortest focal length of the zoom lens, R1 and R2 represent curvature radii of object-side and image-side lens surfaces of a lens (G1) in the first lens unit disposed closest to the object side, respectively, and fF represents a focal length of the focus lens unit.
An image pickup apparatus comprising:
- a zoom lens;
- and
- an image pickup element that receives light of an image formed by the zoom lens, wherein
- the zoom lens is a zoom lens which comprises, in order from an object side to an image side, a first lens unit with a negative refractive power and a rear lens group including one or more lens units, in which intervals between adjacent ones of the lens units are changed during zooming and focusing, wherein
- the first lens unit comprises three or more negative lenses,
- the rear lens group comprises a focus lens unit with a negative refractive power that moves during focusing, and
- the following conditional expressions are satisfied:
- 0.85<|f1|/fW<7.0,
- 0.40<(R1−R2)/(R1+R2)<0.80, and
- 2.0<|fF|/fW<7.0
- where f1 represents a focal length of the first lens unit, fW represents a shortest focal length of the zoom lens, R1 and R2 represent curvature radii of object-side and image-side lens surfaces of a lens (G1) in the first lens unit disposed closest to the object side, respectively, and fF represents a focal length of the focus lens unit.
Dependencies are inferred from the claim text.