Zoom lens and image pickup apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorHirofumi Abe
Life of this patent
Estimating the term…
Abstract
Provided is a zoom lens including, in order from an object side to an image side, first to fourth lens units having positive, negative, positive, and positive refractive powers, respectively. In the zoom lens, during zooming, the first lens unit and the third lens unit do not move, and the second lens unit and the fourth lens unit move with loci different from each other, the first lens unit consists of, in order from the object side to the image side, a negative lens G11, a positive lens G12, and a positive lens G13, and an Abbe number ν1n of a material of the negative lens G11, an average value N1ave of refractive indices of materials of three lenses included in the first lens unit, a focal length f1 of the first lens unit, and a focal length f2 of the second lens unit are appropriately set.
Claims17
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit having a positive refractive power;
- a second lens unit having a negative refractive power;
- a third lens unit having a positive refractive power;
- and
- a fourth lens unit having a positive refractive power,
- wherein during zooming, the first lens unit and the third lens unit are configured to not move, and the second lens unit and the fourth lens unit are configured to move with loci different from each other,
- wherein the first lens unit consists of, in order from the object side to the image side, a negative lens G11, a positive lens G12, and a positive lens G13, and
- wherein the following conditional expressions are satisfied:
- 15.0<v1n<19.0;
- 1.7<N1ave<2.5;
- and
- 2.0<|f1/f2|<5.0,
- where v1n represents an Abbe number of a material of the negative lens G11, N1ave represents an average value of refractive indices of materials of three lenses included in the first lens unit, f1 represents a focal length of the first lens unit, and f2 represents a focal length of the second lens unit.
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit having a positive refractive power;
- a second lens unit having a negative refractive power;
- a third lens unit having a positive refractive power;
- and
- a fourth lens unit having a positive refractive power, wherein during zooming, the first lens unit and the third lens unit are configured to not move, and the second lens unit and the fourth lens unit are configured to move with loci different from each other,
- wherein the first lens unit consists of, in order from the object side to the image side, a negative lens G11, a positive lens G12, and a positive lens G13,
- wherein the third lens unit consists of a positive lens G31,
- wherein at least one lens surface of the positive lens G31 has an aspherical shape, and
- wherein the following conditional expressions are satisfied:
- 15.0<v1n<22.0;
- 1.7<N1ave<2.5;
- and
- 2.0<|f1/f2|<5.0,
- where v1n represents an Abbe number of a material of the negative lens G11, N1ave represents an average value of refractive indices of materials of three lenses included in the first lens unit, f1 represents a focal length of the first lens unit, and f2 represents a focal length of the second lens unit.
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit having a positive refractive power;
- a second lens unit having a negative refractive power;
- a third lens unit having a positive refractive power;
- and
- a fourth lens unit having a positive refractive power,
- wherein during zooming, the first lens unit and the third lens unit are configured to not move, and the second lens unit and the fourth lens unit are configured to move with loci different from each other,
- wherein the first lens unit consists of, in order from the object side to the image side, a negative lens G11, a positive lens G12, and a positive lens G13,
- wherein the fourth lens unit consists of, in order from the object side to the image side, a positive lens, and a cemented lens composed of a negative lens and a positive lens, and
- wherein the following conditional expressions are satisfied:
- 15.0<v1n<22.0;
- 1.7<N1ave<2.5;
- and
- 2.0<|f1/f2|<5.0,
- where v1n represents an Abbe number of a material of the negative lens G11, N1ave represents an average value of refractive indices of materials of three lenses included in the first lens unit, f1 represents a focal length of the first lens unit, and f2 represents a focal length of the second lens unit.
Dependencies are inferred from the claim text.