IMAGING LENS AND IMAGING APPARATUS
An imaging lens of the present disclosure includes, in order from object side toward image plane side, a first lens having a meniscus shape, the meniscus shape having a shape that is positioned near an optical axis and includes a convex surface that faces the object side, a second lens including a convex surface that faces, near the optical axis, the object side, and having, near the optical axis, positive refractive power, a third lens having, near the optical axis, negative refractive power, a fourth lens, a fifth lens, a sixth lens having, near the optical axis, positive refractive power, and a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side, and having an aspherical shape that has an inflection point.
1 . An imaging lens comprising, in order from object side toward image plane side:
a first lens having a meniscus shape, the meniscus shape having a shape that is positioned near an optical axis and includes a convex surface that faces the object side;
a second lens including a convex surface that faces, near the optical axis, the object side, and having, near the optical axis, positive refractive power;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point.
2 . The imaging lens according to claim 1 , wherein a following conditional expression is satisfied:
−0.5< f/f 1<0.23 (1)
where
f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens.
3 . The imaging lens according to claim 1 , wherein following conditional expressions are satisfied:
0<θmax( L 1 R 1)<25 (2)
0.3< R ( L 3 R 2)/ f< 5 (3)
where
θmax (L 1 R 1 ) is a maximum value of a surface angle of a lens surface, on the object side, of the first lens within an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
R (L 3 R 2 ) is radius of curvature of a lens surface, on the image plane side, of the third lens, and
f is a focal length of a lens system as a whole.
4 . The imaging lens according to claim 1 , wherein following conditional expressions are satisfied:
−15<θmin( L 6 R 1)<θmax( L 6 R 1)<8 (4)
−31<θmin( L 6 R 2)<θmax( L 6 R 2)<−5 (5)
where
θmax (L 6 R 1 ) is a maximum value of a surface angle of a lens surface, on the object side, of the sixth lens within a diameter of 30% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmin (L 6 R 1 ) is a minimum value of the surface angle of the lens surface, on the object side, of the sixth lens within the diameter of 30% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmax (L 6 R 2 ) is a maximum value of a surface angle of a lens surface, on the image plane side, of the sixth lens within a diameter of 70% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”), and
θmin (L 6 R 2 ) is a minimum value of the surface angle of the lens surface, on the image plane side, of the sixth lens within the diameter of 70% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
5 . The imaging lens according to claim 1 , wherein a following conditional expression is satisfied:
5<θmax( L 3 R 2)<40 (6)
where
θmax (L 3 R 2 ) is a maximum value of a surface angle of a lens surface, on the image plane side, of the third lens within an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
6 . The imaging lens according to claim 1 , wherein a following conditional expression is satisfied:
0.3< f 12/ f< 2.0 (7)
where
f is a focal length of a lens system as a whole, and
f12 is a composite focal length of the first lens and the second lens.
7 . The imaging lens according to claim 1 , wherein a following conditional expression is satisfied:
−5< f 3/ f<− 0.5 (8)
where
f is a focal length of a lens system as a whole, and
f3 is a focal length of the third lens.
8 . The imaging lens according to claim 1 , wherein a following conditional expression is satisfied:
0.023< T ( L 3)/ f< 0.15 (9)
where
f is a focal length of a lens system as a whole, and
T(L 3 ) is a center thickness of the third lens.
9 . The imaging lens according to claim 1 , wherein a following conditional expression is satisfied:
ν d ( L 1)>50 (10)
where
νd (L 1 ) is Abbe number of the first lens to d line.
10 . The imaging lens according to claim 1 , wherein following conditional expressions are satisfied:
ν d ( L 3)<35 (11)
ν d ( L 5)<35 (12)
where
νd (L 3 ) is Abbe number of the third lens to d line, and
νd (L 5 ) is Abbe number of the fifth lens to the d line.
11 . The imaging lens according to claim 1 , wherein following conditional expressions are satisfied:
ν d ( L 4)>50 (13),
ν d ( L 6)>50 (14)
ν d ( L 7)>50 (15),
where
νd (L 4 ) is Abbe number of the fourth lens to d line,
νd (L 6 ) is Abbe number of the sixth lens to the d line, and
νd (L 7 ) is Abbe number of the seventh lens to the d line.
12 . An imaging lens comprising, in order from object side toward image plane side:
a first lens;
a second lens having, near an optical axis, positive refractive power;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point,
wherein a following conditional expression is satisfied,
−0.5< f/f 1<0.23 (1)
where
f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens.
13 . The imaging lens according to claim 12 , wherein a following conditional expression is satisfied:
0.3< R ( L 3 R 2)/ f< 5 (3)
where
R (L 3 R 2 ) is radius of curvature of a lens surface, on the image plane side, of the third lens, and
f is the focal length of the lens system as a whole.
14 . The imaging lens according to claim 12 , wherein following conditional expressions are satisfied:
−15<θmin( L 6 R 1)<θmax( L 6 R 1)<8 (4)
−31<θmin( L 6 R 2)<θmax( L 6 R 2)<−5 (5)
where
θmax (L 6 R 1 ) is a maximum value of a surface angle of a lens surface, on the object side, of the sixth lens within a diameter of 30% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmin (L 6 R 1 ) is a minimum value of the surface angle of the lens surface, on the object side, of the sixth lens within the diameter of 30% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmax (L 6 R 2 ) is a maximum value of a surface angle of a lens surface, on the image plane side, of the sixth lens within a diameter of 70% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”), and
θmin (L 6 R 2 ) is a minimum value of the surface angle of the lens surface, on the image plane side, of the sixth lens within the diameter of 70% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
15 . The imaging lens according to claim 12 , wherein a following conditional expression is satisfied:
5<θmax( L 3 R 2)<40 (6)
where
θmax (L 3 R 2 ) is a maximum value of a surface angle of a lens surface, on the image plane side, of the third lens within an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
16 . The imaging lens according to claim 12 , wherein a following conditional expression is satisfied:
0.3< f 12/ f< 2.0 (7)
where
f is the focal length of the lens system as a whole, and
f12 is a composite focal length of the first lens and the second lens.
17 . The imaging lens according to claim 12 , wherein a following conditional expression is satisfied:
−5< f 3/ f<− 0.5 (8)
where
f is the focal length of the lens system as a whole, and
f3 is a focal length of the third lens.
18 . The imaging lens according to claim 12 , wherein a following conditional expression is satisfied:
0.023< T ( L 3)/ f< 0.15 (9)
where
f is the focal length of the lens system as a whole, and
T (L 3 ) is a center thickness of the third lens.
19 . An imaging apparatus provided with an imaging lens and an imaging device that outputs an imaging signal corresponding to an optical image formed by the imaging lens, the imaging lens comprising, in order from object side toward image plane side:
a first lens having a meniscus shape, the meniscus shape having a shape that is positioned near an optical axis and includes a convex surface that faces the object side;
a second lens including a convex surface that faces, near the optical axis, the object side, and having, positive refractive power near the optical axis;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point.
20 . An imaging apparatus provided with an imaging lens and an imaging device that outputs an imaging signal corresponding to an optical image formed by the imaging lens, the imaging lens comprising, in order from object side toward image plane side:
a first lens;
a second lens having, near the optical axis, positive refractive power;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point,
wherein a following conditional expression is satisfied,
−0.5< f/f 1<0.23 (1)
where
f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens.