Imaging lens and imaging apparatus
View Patent ↗The imaging lens consists of, in order from an object side, a positive first lens L 1 , a negative second lens L 2 , a positive third lens L 3 , and a positive fourth lens L 4 . Conditional expressions relating to a focal length f of an entire system, a combined focal length f234 of the second lens L 2 to the fourth lens L 4 , an Abbe number νd1 of the first lens L 1 , an Abbe number νd2 of the second lens L 2 , a radius of curvature R1 of a surface of the first lens L 1 on the object side, and a radius of curvature R2 of a surface of the first lens L 1 on an image side: 0.4<f/f234<2; νd1<50; 5<νd1−νd2<26; −5<(R1+R2)/(R1−R2)<−0.9 are satisfied.
1. An imaging lens consisting of, in order from an object side:
a first lens having positive refractive power;
a second lens having negative refractive power;
a third lens having positive refractive power; and
a fourth lens having positive refractive power,
wherein all of the following conditional expressions (1) to (4) are satisfied;
0.4< f/f 234<2 (1)
ν d 1<50 (2)
5<ν d 1−ν d 2<26 (3)
−5<( R 1+ R 2)/( R 1− R 2)<−0.9 (4)
where
f: a focal length of an entire system
f234: a combined focal length of the second lens, the third lens, and the fourth lens
νd1: an Abbe number for d-line of the first lens
νd2: an Abbe number for d-line of the second lens
R1: a radius of curvature of a surface of the first lens on the object side
R2: a radius of curvature of a surface of the first lens on an image side.
2. The imaging lens according to claim 1 ,
wherein the following conditional expression (1-1) is satisfied;
0.55< f/f 234<1.45 (1-1).
3. The imaging lens according to claim 1 ,
wherein the following conditional expression (5) is satisfied;
0.2< D 1/ f (5)
where
D1: a thickness of the first lens on an optical axis.
4. The imaging lens according to claim 2 ,
wherein the following conditional expression (5) is satisfied;
0.2< D 1/ f (5)
where
D1: a thickness of the first lens on an optical axis.
5. The imaging lens according to 1 ,
wherein the following conditional expression (6) is satisfied;
27<(ν d 3+ν d 4)/2−ν d 2<34 (6)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
6. The imaging lens according to 2 ,
wherein the following conditional expression (6) is satisfied;
27<(ν d 3+ν d 4)/2−ν d 2<34 (6)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
7. The imaging lens according to 3 ,
wherein the following conditional expression (6) is satisfied;
27<(ν d 3+ν d 4)/2−ν d 2<34 (6)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
8. The imaging lens according to 4 ,
wherein the following conditional expression (6) is satisfied;
27<(ν d 3+ν d 4)/2−ν d 2<34 (6)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
9. The imaging lens according to claim 1 ,
wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
10. The imaging lens according to claim 2 ,
wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
11. The imaging lens according to claim 3 ,
wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
12. The imaging lens according to claim 4 , wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
13. The imaging lens according to claim 5 ,
wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
14. The imaging lens according to claim 6 ,
wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
15. The imaging lens according to claim 7 ,
wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
16. The imaging lens according to claim 8 ,
wherein the following conditional expression (7) is satisfied;
−30<ν d 1−(ν d 3+ν d 4)/2<−3 (7)
where
νd3: an Abbe number for d-line of the third lens
νd4: an Abbe number for d-line of the fourth lens.
17. The imaging lens according to claim 1 ,
wherein the following conditional expression (8) is satisfied;
−2.5<( R 8+ R 9)/( R 8− R 9)<−0.5 (8)
where
R8: a radius of curvature of a surface of the fourth lens on the object side
R9: a radius of curvature of a surface of the fourth lens on the image side.
18. The imaging lens according to claim 2 ,
wherein the following conditional expression (8) is satisfied;
−2.5<( R 8+ R 9)/( R 8− R 9)<−0.5 (8)
where
R8: a radius of curvature of a surface of the fourth lens on the object side
R9: a radius of curvature of a surface of the fourth lens on the image side.
19. The imaging lens according to claim 1 ,
wherein the following conditional expression (9) is satisfied;
40°<2ω<60° (9)
where
2ω: a maximum full angle of view, the unit of which is degree (°).
20. An imaging apparatus comprising:
the imaging lens according to claim 1 .