ZOOM LENS AND IMAGING APPARATUS
First Claim
1. A zoom lens comprising, in order from an object side:
- a first lens group that has a positive refractive power and remains stationary with respect to an image plane during zooming;
a plurality of movable lens groups that move by changing distances between groups adjacent to each other in a direction of an optical axis during zooming; and
a final lens group that has a positive refractive power and remains stationary with respect to the image plane during zooming,wherein in the plurality of movable lens groups, at least one movable lens group has a negative refractive power,wherein the first lens group has an image side positive lens, which is a positive lens disposed to be closest to the image side, and one or more positive lenses which are disposed to be closer to the object side than the image side positive lens, andwherein all Conditional Expressions (1) to (5) are satisfied,
0.25<
fl/fz<
0.7
(1),
55<
ν
z<
68
(2),
15<
ν
mx−
ν
z<
50
(3),
2.395<
Nz+0.012×
ν
z
(4), and
0.634<
θ
gFz+0.001625×
ν
z<
0.647
(5),where fl is a focal length of the first lens group,fz is a focal length of the image side positive lens,ν
z is an Abbe number of the image side positive lens at the d line,ν
mx is an Abbe number of a positive lens, of which the Abbe number at the d line is at a maximum value, among positive lenses disposed to be closer to the object side than the image side positive lens,Nz is a refractive index of the image side positive lens at the d line, andθ
gFz is a partial dispersion ratio of the image side positive lens between the g line and the F line.
1 Assignment
0 Petitions
Accused Products
Abstract
The zoom lens includes, in order from the object side: a first lens group G1 that has a positive refractive power and remains stationary during zooming; a plurality of movable lens groups that move by changing distances between groups adjacent to each other in a direction of an optical axis during zooming; and a final lens group Ge that has a positive refractive power and remains stationary during zooming. At least one movable lens group has a negative refractive power. The first lens group G1 has an image side positive lens, which is a positive lens disposed to be closest to the image side, and one or more positive lenses which are disposed to be closer to the object side than the image side positive lens. The zoom lens satisfies predetermined conditional expressions relating to the image side positive lens.
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Citations
20 Claims
-
1. A zoom lens comprising, in order from an object side:
-
a first lens group that has a positive refractive power and remains stationary with respect to an image plane during zooming; a plurality of movable lens groups that move by changing distances between groups adjacent to each other in a direction of an optical axis during zooming; and a final lens group that has a positive refractive power and remains stationary with respect to the image plane during zooming, wherein in the plurality of movable lens groups, at least one movable lens group has a negative refractive power, wherein the first lens group has an image side positive lens, which is a positive lens disposed to be closest to the image side, and one or more positive lenses which are disposed to be closer to the object side than the image side positive lens, and wherein all Conditional Expressions (1) to (5) are satisfied,
0.25<
fl/fz<
0.7
(1),
55<
ν
z<
68
(2),
15<
ν
mx−
ν
z<
50
(3),
2.395<
Nz+0.012×
ν
z
(4), and
0.634<
θ
gFz+0.001625×
ν
z<
0.647
(5),where fl is a focal length of the first lens group, fz is a focal length of the image side positive lens, ν
z is an Abbe number of the image side positive lens at the d line,ν
mx is an Abbe number of a positive lens, of which the Abbe number at the d line is at a maximum value, among positive lenses disposed to be closer to the object side than the image side positive lens,Nz is a refractive index of the image side positive lens at the d line, and θ
gFz is a partial dispersion ratio of the image side positive lens between the g line and the F line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification