Imaging lens and imaging apparatus
View Patent ↗The imaging lens consists essentially of a negative first lens having a meniscus shape with a convex surface toward the object side; a negative second lens, a positive third lens; and a positive lens. When the focal length of the entire system is f, a half angle of view is ω, and the distance from the object-side surface of the first lens to the imaging plane along the optical axis is L, conditional formula (1) below is satisfied: 0.78<2* f *tan(ω/2)/ L +0.005*ω<1.00 (1).
1. An imaging lens of the present invention consists essentially of:
a negative first lens having a meniscus shape with a convex surface toward the object side;
a negative second lens, a point along the optical axis at the image-side surface of which is more toward the object side than points on both ends of the effective diameter of the image-side surface;
a positive third lens;
an aperture stop; and
a positive fourth lens in this order from the object side, wherein
conditional formula (1) below is satisfied:
0.78<2* f *tan(ω/2)/ L+ 0.005*ω<1.00 (1),
where
f: the focal length of the entire system,
ω: a half angle of view, and
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (back focus corresponds to an air converted length).
2. The imaging lens of claim 1 , that satisfies conditional formula (2) below:
0.13< f 3/ L< 0.24 (2),
where
f3: the focal length of the third lens, and
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (the back focus corresponds to an air converted length).
3. The imaging lens of claim 1 , that satisfies conditional formula (3) below:
0.19< f 4/ L< 0.25 (3),
where
f4: the focal length of the fourth lens, and
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (the back focus corresponds to an air converted length).
4. The imaging lens of claim 1 , that satisfies conditional formula (4) below:
3.2< d 2/ d 4<20.0 (4),
where
d2: the distance between the first lens and the second lens along the optical axis, and
d4: the distance between the second lens and the third lens along the optical axis.
5. The imaging lens of claim 1 , that satisfies conditional formula (5) below:
0.31< f/f 34<1.0 (5),
where
f34: the combined focal length of the third lens and the fourth lens, and
f: the focal length of the entire system.
6. The imaging lens of claim 1 , that satisfies conditional formula (6) below:
0.1< d 6/ f< 0.7 (6),
where
d6: the distance between the third lens and the fourth lens along the optical axis, and
f: the focal length of the entire system.
7. The imaging lens of claim 1 , that satisfies conditional formulas (7) through (10) below:
vd 1>40 (7)
vd 2>50 (8)
vd 3<40 (9)
vd 4>50 (10),
where
vd1: the Abbe number with respect to the d-line of the material of the first lens,
vd2: the Abbe number with respect to the d-line of the material of the second lens,
vd3: the Abbe number with respect to the d-line of the material of the third lens, and
vd4: the Abbe number with respect to the d-line of the material of the fourth lens.
8. The imaging lens of claim 1 , that satisfies conditional formula (1-1) below:
0.80<2* f *tan(ω/2)/ L+ 0.005*ω<1.00 (1-1),
where
f: the focal length of the entire system,
ω: a half angle of view, and
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (the back focus corresponds to an air converted length).
9. The imaging lens of claim 1 , that satisfies conditional formula (4-1) below:
4.0< d 2/ d 4<20.0 (4-1),
where
d2: the distance between the first lens and the second lens along the optical axis, and
d4: the distance between the second lens and the third lens along the optical axis.
10. The imaging lens of claim 1 , that satisfies conditional formula (5-1) below:
0.35< f/f 34<0.58 (5-1),
where
f34: the combined focal length of the third lens and the fourth lens, and
f: the focal length of the entire system.
11. The imaging lens of claim 1 , that satisfies conditional formula (6-1) below:
0.1< d 6/ f< 0.6 (6-1),
where
d6: the distance between the third lens and the fourth lens along the optical axis, and
f: the focal length of the entire system.
12. An imaging apparatus comprising:
imaging lens of claim 1 .