Zoom lens, image pickup apparatus having the same, and imaging system
AssigneeCanon Kabushiki Kaisha
InventorKenji SHINOHARA
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 negative refractive power and a second lens unit having positive refractive power. A distance between adjacent lens units changes during zooming. The first lens unit includes a plurality of lenses, the plurality of lenses consisting of a negative lens having a concave lens surface on the image side, and a positive lens having a convex lens surface on the object side and disposed on the image side of the negative lens via an air gap. A predetermined condition is satisfied.
Claims19
A zoom lens comprising, in order from an object side to an image side, a first lens unit having negative refractive power and a second lens unit having positive refractive power,
- wherein a distance between adjacent lens units changes during zooming,
- wherein the first lens unit includes a plurality of lenses, the plurality of lenses consisting of a negative lens having a concave lens surface on the image side, and a positive lens having a convex lens surface on the object side and disposed on the image side of the negative lens via an air gap, and,
- wherein the following inequalities are satisfied:
- −7.00<f12/f11<−3.70
- 0.40<(R1f+R2r)/(R1f−R2r)<1.00
- where f11 is a focal length of the negative lens, f12 is a focal length of the positive lens, R1f is a radius of curvature of a lens surface on the object side of the negative lens, and R2r is a radius of curvature of a lens surface on the image side of the positive lens.
An image pickup apparatus comprising:
- a zoom lens;
- and
- an image sensor configured to receive an image formed by the zoom lens,
- wherein the zoom lens includes, in order from an object side to an image side, a first lens unit having negative refractive power and a second lens unit having positive refractive power,
- wherein a distance between adjacent lens units changes during zooming,
- wherein the first lens unit includes a plurality of lenses, the plurality of lenses consisting of a negative lens having a concave lens surface on the image side, and a positive lens having a convex lens surface on the object side and disposed on the image side of the negative lens via an air gap, and,
- wherein the following inequalities are satisfied:
- −7.00<f12/f11<−3.70
- 0.40(R1f+R2r)/(R1f−R2r)<1.00
- where f11 is a focal length of the negative lens, f12 is a focal length of the positive lens, R1f is a radius of curvature of a lens surface on the object side of the negative lens, and R2r is a radius of curvature of a lens surface on the image side of the positive lens.
An imaging system comprising:
- a zoom lens;
- and
- a control unit configured to control the zoom lens during zooming,
- wherein the zoom lens includes, in order from an object side to an image side, a first lens unit having negative refractive power and a second lens unit having positive refractive power,
- wherein a distance between adjacent lens units changes during zooming,
- wherein the first lens unit includes a plurality of lenses, the plurality of lenses consisting of a negative lens having a concave lens surface on the image side, and a positive lens having a convex lens surface on the object side and disposed on the image side of the negative lens via an air gap, and,
- wherein the following inequalities are satisfied:
- −7.00<f12/f11<−3.70
- 0.40<(R1f+R2r)/(R1f−R2r)<1.00
- where f11 is a focal length of the negative lens, f12 is a focal length of the positive lens, R1f is a radius of curvature of a lens surface on the object side of the negative lens, and R2r is a radius of curvature of a lens surface on the image side of the positive lens.
Dependencies are inferred from the claim text.