Zoom lens and image pickup apparatus
AssigneeCanon Kabushiki Kaisha
InventorShoichi Takemoto
Life of this patent
Estimating the term…
Abstract
Provided is a zoom lens including in order from an object side: a positive first unit configured not to move for zooming; a negative second unit configured to move for zooming; a positive third unit configured to move for zooming; a negative fourth unit configured to move for zooming; and a positive rear unit including at least one lens unit, wherein the fourth unit is configured to move for focusing, and wherein a focal length of the fourth unit, a focal length of the rear unit at a telephoto end, a focal length of the zoom lens at a wide angle end, amounts of movement of the second and third units from the wide angle end to the telephoto end, a half angle of view at the wide angle end, an amount of displacement of an in-focus position.
Claims10
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 second lens unit having a negative refractive power and configured to move for zooming;
- a third lens unit having a positive refractive power and configured to move for zooming;
- a fourth lens unit having a negative refractive power and configured to move for zooming;
- and
- a rear lens unit having a positive refractive power and including at least one lens unit,
- wherein the fourth lens unit is configured to move for focusing, and
- wherein conditional expressions
- −0.60<f4/fR<−0.20;
- −5.00<M2/M3<−1.50;
- and
- −0.42<dskt/(fw×tan ωw)<−0.15
- are satisfied, where f4 represents a focal length of the fourth lens unit, fR represents a focal length of the rear lens unit at a telephoto end, fw represents a focal length of the zoom lens at a wide angle end, M2 represents an amount of movement of the second lens unit from the wide angle end to the telephoto end, M3 represents an amount of movement of the third lens unit from the wide angle end to the telephoto end, ωw represents a half angle of view at the wide angle end, “dskt” (mm) represents an amount of displacement of a focus position in a case where the fourth lens unit moves toward the image side by 1 (mm) in a state in which the focus position is at infinity at the telephoto end, and a sign of an amount of movement of a lens unit is negative in a case where the lens unit moves toward the object side, and the sign is positive in a case where the lens unit moves toward the image side with respect to zooming from the wide angle end to the telephoto end.
An image pickup apparatus, comprising:
- 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 second lens unit having a negative refractive power and configured to move for zooming;
- a third lens unit having a positive refractive power and configured to move for zooming;
- a fourth lens unit having a negative refractive power and configured to move for zooming;
- and
- a rear lens unit having a positive refractive power and including at least one lens unit,
- wherein the fourth lens unit is configured to move for focusing, and
- wherein conditional expressions
- −0.60<f4/fR<−0.20;
- −5.00<M2/M3<−1.50;
- and
- −0.42<dskt/(fw×tan ωw)<−0.15
- are satisfied, where f4 represents a focal length of the fourth lens unit, fR represents a focal length of the rear lens unit at a telephoto end, fw represents a focal length of the zoom lens at a wide angle end, M2 represents an amount of movement of the second lens unit from the wide angle end to the telephoto end, M3 represents an amount of movement of the third lens unit from the wide angle end to the telephoto end, ωw represents a half angle of view at the wide angle end, “dskt” (mm) represents an amount of displacement of a focus position in a case where the fourth lens unit moves toward the image side by 1 (mm) in a state in which the focus position is at infinity at the telephoto end, and a sign of an amount of movement of a lens unit is negative in a case where the lens unit moves toward the object side, and the sign is positive in a case where the lens unit moves toward the image side with respect to zooming from the wide angle end to the telephoto end;
- and
- an image pickup element arranged on an image plane of the zoom lens.
Dependencies are inferred from the claim text.