Zoom lens and image pickup apparatus
AssigneeCanon Kabushiki Kaisha
InventorKazuya Shimomura
Life of this patent
Estimating the term…
Abstract
A zoom lens including from object side: a positive first unit; at least one negative unit moving toward image side for zooming from wide to telephoto; and at least two positive units each moving toward object side for the zooming, in which the positive first unit includes a biconcave lens closest to object side, in which an N unit is one of the at least one negative unit and having largest amount of movement during the zooming, and P unit is one of the at least two positive units having largest amount of movement during the zooming; in which focal lengths of the first lens unit, of the zoom lens at wide end and telephoto end, a difference between distances from the N unit to image plane at telephoto end and at wide end and a distance from the P unit to image plane at telephoto end are appropriately set.
Claims15
A zoom lens comprising in order from an object side to an image side:
- a first lens unit having a positive refractive power and configured not to move for zooming;
- a first intermediate unit which consists of at least one lens unit having a negative refractive power and configured to move toward the image side for zooming from a wide angle end to a telephoto end;
- and
- a second intermediate unit which consists of at least two lens units each having a positive refractive power and configured to move toward the object side for zooming from the wide angle end to the telephoto end,
- wherein an interval between each pair of adjacent lens units is changed during zooming,
- wherein the first lens unit includes a biconcave lens disposed closest to the object side,
- wherein a lens unit included in the at least one lens unit having the negative refractive power and having a largest amount of movement during zooming from the wide angle end to the telephoto end is defined as an N lens unit, and a lens unit included in the at least two lens units each having the positive refractive power and having a largest amount of movement during zooming from the wide angle end to the telephoto end is defined as a P lens unit;
- wherein the following inequalities are satisfied,
- 4.35
- <
- ft
- /
- f
-
- 1
- <
- 6.
- 1.
- <
- ❘
- "\[LeftBracketingBar]"
- mn
- /
- mp
- ❘
- "\[RightBracketingBar]"
- ≤
- 1.934
- 0.02
- <
- fw
- /
- f
-
- 1
- <
- 0.035
- where f1 represents a focal length of the first lens unit, fw represents a focal length of the zoom lens at the wide angle end, ft represents a focal length of the zoom lens at the telephoto end, mn represents a difference between a distance from the N lens unit to an image plane at the wide-angle end and a distance from the N lens unit to the image plane at the telephoto end, and mp represents a difference between distances from the P lens unit to the image plane at the wide-angle end and a distance from the P lens unit to the image plane at the telephoto end.
An image pickup apparatus comprising a zoom lens and an image pickup element configured to pickup an image formed by the zoom lens,
- wherein the zoom lens comprises in order from an object side to an image side:
- a first lens unit having a positive refractive power and configured not to move for zooming;
- a first intermediate unit which consists of at least one lens unit having a negative refractive power and configured to move toward the image side for zooming from a wide angle end to a telephoto end;
- and
- a second intermediate unit which consists of at least two lens units each having a positive refractive power and configured to move toward the object side for zooming from the wide angle end to the telephoto end,
- wherein an interval between each pair of adjacent lens units is changed during zooming,
- wherein the first lens unit includes a biconcave lens disposed closest to the object side,
- wherein a lens unit included in the at least one lens unit having the negative refractive power and having a largest amount of movement during zooming from the wide angle end to the telephoto end is defined as an N lens unit, and a lens unit included in the at least two lens units each having the positive refractive power and having a largest amount of movement during zooming from the wide angle end to the telephoto end is defined as a P lens unit;
- wherein the following inequalities are satisfied,
- 4.35
- <
- ft
- /
- f
-
- 1
- <
- 6.
- 1.
- <
- ❘
- "\[LeftBracketingBar]"
- mn
- /
- mp
- ❘
- "\[RightBracketingBar]"
- ≤
- 1.934
- 0.02
- <
- fw
- /
- f
-
- 1
- <
- 0.035
- where f1 represents a focal length of the first lens unit, fw represents a focal length of the zoom lens at the wide angle end, ft represents a focal length of the zoom lens at the telephoto end, mn represents a difference between a distance from the N lens unit to an image plane at the wide-angle end and a distance from the N lens unit to the image plane at the telephoto end, and mp represents a difference between distances from the P lens unit to the image plane at the wide-angle end and a distance from the P lens unit to the image plane at the telephoto end.
Dependencies are inferred from the claim text.