Imaging lens and imaging apparatus provided with the same
View Patent ↗An imaging lens consists of five lenses consisting of, in order from the object side, a biconvex first lens, a biconcave second lens, a positive third lens having a meniscus shape with the convex surface toward the image side, a positive fourth lens having a meniscus shape with the convex surface toward the image side, and a negative fifth lens having a concave surface toward the image side, and having at least one inflection point on the image-side surface thereof, wherein condition expression (1), 0<f/f3<0.6, relating to the focal length f of the entire system and the focal length f3 of the third lens, and condition expression (2), 0.12<D7/f<0.3, relating to the focal length f of the entire system and the distance D7 between the third lens and the fourth lens along the optical axis are satisfied.
1. An imaging lens consisting of five lenses consisting of, in order from an object side:
a first lens having a biconvex shape;
a second lens having a biconcave shape;
a third lens having a positive refractive power and having a meniscus shape with the convex surface toward an image side;
a fourth lens having a positive refractive power and having a meniscus shape with the convex surface toward the image side; and
a fifth lens having a negative refractive power, having a concave surface toward the image side, and having at least one inflection point on the image-side surface thereof,
wherein the condition expression below is satisfied:
0< f/f 3<0.6 (1), and
0.12< D 7/ f< 0.3 (2),
where f is a focal length of the entire system, f 3 is a focal length of the third lens, and D 7 is a distance between the third lens and the fourth lens along the optical axis.
2. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
1.5< f/f 1<3 (3),
where f 1 is a focal length of the first lens.
3. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
−5< f/f 5<−1 (4),
where f 5 is a focal length of the fifth lens.
4. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0< f 1/ f 3<0.5 (5),
where f 1 is a focal length of the first lens.
5. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0<( R 3 f−R 3 r )/( R 3 f+R 3 r )<0.6 (6),
where R 3 f is a paraxial radius of curvature of the object-side surface of the third lens, and R 3 r is a paraxial radius of curvature of the image-side surface of the third lens.
6. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0.2< f ·tan ω/ R 5 r< 10 (7),
where ω is a half angle of view, and R 5 r is a paraxial radius of curvature of the image-side surface of the fifth lens.
7. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
−2< f/f 2<−0.5 (8),
where f 2 is a focal length of the second lens.
8. The imaging lens as claimed in claim 1 , wherein an aperture stop is disposed on the object side of the object-side surface of the second lens.
9. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0< f/f 3<0.5 (1-1).
10. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0.13< D 7/ f< 0.25 (2-1).
11. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
1.7< f/f 1<2.7 (3-1),
where f 1 is a focal length of the first lens.
12. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
−4< f/f 5<−1.2 (4-1),
where f 5 is a focal length of the fifth lens.
13. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0< f 1/ f 3<0.4 (5-1),
where f 1 is a focal length of the first lens.
14. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0<( R 3 f−R 3 r )/( R 3 f+R 3 r )<0.55 (6-1),
where R 3 f is a paraxial radius of curvature of the object-side surface of the third lens, and R 3 r is a paraxial radius of curvature of the image-side surface of the third lens.
15. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0.5< f ·tan ω/ R 5 r< 5 (7-1),
where ω is a half angle of view, and R 5 r is a paraxial radius of curvature of the image-side surface of the fifth lens.
16. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
−1.8< f/f 2<−0.7 (8-1),
where f 2 is a focal length of the second lens.
17. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0< f/f 3<0.4 (1-2).
18. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
0.14< D 7/ f< 0.2 (2-2).
19. The imaging lens as claimed in claim 1 , wherein the condition expression below is further satisfied:
1.85< f/f 1<2.5 (3-2),
where f 1 is a focal length of the first lens.
20. An imaging apparatus comprising the imaging lens as claimed in claim 1 .