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US 12,066,608 B2Granted
Zoom lens and image pickup apparatus
AssigneeCanon Kabushiki Kaisha
InventorJunya Ichimura
Life of this patent
Estimating the term…
Abstract
A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, a fourth lens unit having a negative refractive power, and a rear lens unit having a positive refractive power and disposed closest to an image plane. During zooming from a wide-angle end to a telephoto end, the second lens unit moves to the object side, and each distance between adjacent lens units changes. A predetermined condition is satisfied.
Claims27
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a third lens unit having a negative refractive power;
- a fourth lens unit having a negative refractive power;
- and
- a rear lens unit having a positive refractive power and disposed closest to an image plane,
- wherein during zooming from a wide-angle end to a telephoto end, the second lens unit moves to the object side, and each distance between adjacent lens units changes,
- wherein the first lens unit includes a first lens element disposed at a most-object side position and a second lens element disposed adjacent on the image side to the first lens element,
- wherein the second lens element is made of multiple materials that are different from each other,
- wherein the following inequality is satisfied:
- 1.553≤Nd12≤1.633
- where the Nd12 is average refractive index of the second lens element,
- wherein the second lens unit consists of, in order from the object side to the image side, a first sub-lens unit having a plurality of lenses, a diaphragm, and a second sub-lens unit having a plurality of lenses,
- wherein the first sub-lens unit, the diaphragm, and the second sub-lens unit are configured to integrally move during zooming from a wide-angle end to a telephoto end, and
- wherein following inequalities are satisfied:
- −3.7≤fg1/fw≤−1.5
- −0.10≤mR/BFw≤0.30
- where fg1 represents a focal length of the first lens element, fw represents a focal length of the zoom lens at the wide-angle end, BFw represents a back focus at the wide-angle end, mR represents a moving amount of the rear lens unit during zooming from the wide-angle end to the telephoto end, and a sign of the moving amount is positive when a position of the rear lens unit at the telephoto end is closer to the object than a position of the rear lens unit at the wide-angle end, and is negative when a position of the rear lens unit at the telephoto end is closer to the image plane than the position of the rear lens unit at the wide-angle end.
15 more elements
An image pickup apparatus comprising:
- a zoom lens including, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a third lens unit having a negative refractive power;
- a fourth lens unit having a negative refractive power;
- and
- a rear lens unit having a positive refractive power and disposed closest to an image plane,
- wherein during zooming from a wide-angle end to a telephoto end, the second lens unit moves to the object side, and each distance between adjacent lens units changes,
- wherein the first lens unit includes a first lens element disposed at a most-object side position and a second lens element disposed adjacent on the image side to the first lens element,
- wherein the second lens element is made of multiple materials that are different from each other,
- wherein the following inequality is satisfied:
- 1.553≤Nd12≤1.633
- where the Nd12 is average refractive index of the second lens element,
- wherein the second lens unit consists of, in order from the object side to the image side, a first sub-lens unit having a plurality of lenses, a diaphragm, and a second sub-lens unit having a plurality of lenses,
- wherein the first sub-lens unit, the diaphragm, and the second sub-lens unit are configured to integrally move during zooming from a wide-angle end to a telephoto end, and
- wherein following inequalities are satisfied:
- −3.7≤fg1/fw≤−1.5
- −0.10≤mR/BFw≤0.30
- where fg1 represents a focal length of the first lens element, fw represents a focal length of the zoom lens at the wide-angle end, BFw represents a back focus at the wide-angle end, mR represents a moving amount of the rear lens unit during zooming from the wide-angle end to the telephoto end, and a sign of the moving amount is positive when a position of the rear lens unit at the telephoto end is closer to the object than a position of the rear lens unit at the wide-angle end, and is negative when a position of the rear lens unit at the telephoto end is closer to the image plane than the position of the rear lens unit at the wide-angle end;
- and
- an image sensor configured to capture the object via the zoom lens.
18 more elements
Dependencies are inferred from the claim text.