Imaging lens and imaging apparatus
View Patent ↗An imaging lens is provided and includes: in order from an object side thereof, a first lens of a negative lens having a concave surface on an image side thereof and having at least one aspheric surface; a second lens of a positive lens having at least one aspheric surface; a stop; and a third lens of a positive lens having a convex surface on the image side thereof and at least one aspheric surface. The following Conditional Expressions (1) and (2) are satisfied. 1.5< vd 3/ vd 2 (1) 0.0<| f 1/ f 23|<0.5 (2) In which vd2 represents an Abbe number of the second lens at the d-line, vd3 represents an Abbe number of the third lens at the d-line, f1 represent a focal length of the first lens, and f23 represents a composite focal length of the second and third lenses.
1. An imaging lens comprising: in order from an object side thereof,
a first lens of a negative lens having a concave surface on an image side thereof and having at least one aspheric surface;
a second lens of a positive lens having at least one aspheric surface;
a stop; and
a third lens of a positive lens having a convex surface on the image side thereof and at least one aspheric surface,
wherein the following Conditional Expressions (1) and (2) are satisfied:
1.5 <vd 3 /vd 2 (1)
0.0 <|f 1 /f 23|<0.5 (2)
wherein
vd2 represents an Abbe number of the second lens at the d-line,
vd3 represents an Abbe number of the third lens at the d-line,
f1 represent a focal length of the first lens, and
f23 represents a composite focal length of the second and third lenses.
2. The imaging lens according to claim 1 , wherein the following Conditional Expression (3) is satisfied:
1.5 <|RX 2 |/|R 2| (3)
wherein
|R2| represents an absolute value of a radius of curvature at the center of the image-side surface of the first lens, and
|RX2| represents an absolute value of a radius of curvature at an effective diameter edge of the image-side surface of the first lens.
3. The imaging lens according to claim 1 , wherein the following Conditional Expression (4) is satisfied:
0.8 <f 2 /f 3<2.2 (4)
wherein
f2 represents a focal length of the second lens, and
f3 represents a focal length of the third lens.
4. The imaging lens according to claim 1 , wherein the following Conditional Expression (5) is satisfied:
5.0 <L/f< 12.0 (5)
wherein
L represents a distance along an optical axis from an object-side surface of the first lens to an imaging plane of the imaging lens; and
f represents a focal length of the imaging lens.
5. The imaging lens according to claim 1 , wherein the first lens has an Abbe number of 40 or more at the d-line, the third lens has an Abbe number of 40 or more at the d-line, and the second lens has an Abbe number of 29 or less at the d-line.
6. The imaging lens according to claim 1 , wherein the following Conditional Expression (6) is satisfied:
1.0 <Bf/f< 2.5 (6)
wherein
Bf represents a distance along an optical axis from an image-side surface of a lens closest to the image side to an imaging plane of the imaging lens, and
f represents a focal length of the imaging lens.
7. The imaging lens according to claim 1 , wherein the following Conditional Expression (7) is satisfied:
D 1 /f< 4 (7)
wherein
f represents a focal length of the imaging lens, and
D1 represents a center thickness of the first lens.
8. The imaging lens according to claim 1 , wherein the following Conditional Expression (8) is satisfied:
0.5 <|R 4 /D 3|<20.0 (8)
wherein
R4 represents a radius of curvature of an image-side surface of the second lens, and
D3 represents a center thickness of the second lens.
9. An imaging apparatus comprising an imaging lens according to claim 1 .