Imaging lens and imaging apparatus equipped with the imaging lens
View Patent ↗An imaging lens, consisting essentially of six lenses, composed of in order from the object side, a first lens having a positive refractive power with a convex surface on the object side, a second lens having a negative refractive power, a third lens having a convex surface on the object side, a fourth lens having a positive refractive power, a fifth lens having a negative refractive power, and a sixth lens having a negative refractive power, in which predetermined conditional expressions are satisfied.
1. An imaging lens, consisting of six lenses, composed of, in order from the object side:
a first lens having a positive refractive power with a convex surface on the object side;
a second lens having a negative refractive power;
a third lens having a convex surface on the object side;
a fourth lens having a positive refractive power;
a fifth lens having a negative refractive power; and
a sixth lens having a negative refractive power, wherein the following conditional expressions are satisfied:
1.65< f/f 1<2 (1)
−1.65< f/f 2<−0.8 (2)
0.5< f/f 4<1.7 (3)
where:
f is the focal length of the entire system;
f1 is the focal length of the first lens;
f2 is the focal length of the second lens; and
f4 is the focal length of the fourth lens.
2. The imaging lens of claim 1 , wherein the second lens has a meniscus shape with a convex surface on the object side.
3. The imaging lens of claim 1 , wherein the third lens has a meniscus shape with a convex surface on the object side.
4. The imaging lens of claim 1 , wherein the fourth lens has a meniscus shape with a concave surface on the object side.
5. The imaging lens of claim 1 , wherein the fifth lens has a concave surface on the object side.
6. The imaging lens of claim 1 , further comprising an aperture stop located on the object side of the object side surface of the second lens.
7. The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
−1.5< f/f 6<−0.3 (4)
where f6 is the focal length of the sixth lens.
8. The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
−5<( L 4 r+L 4 f )/( L 4 r−L 4 f )<−1.5 (5)
where:
L4r is the paraxial radius of curvature of the image side surface of the fourth lens; and
L4f is the paraxial radius of curvature of the object side surface of the fourth lens.
9. The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
−1.6< f/f 2<−0.9 (2-1).
10. The imaging lens of claim 9 , wherein the following conditional expression is further satisfied:
−1.5< f/f 2<−1 (2-2).
11. The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
0.7< f/f 4<1.6 (3-1).
12. The imaging lens of claim 11 , wherein the following conditional expression is further satisfied:
0.8< f/f 4<1.5 (3-2).
13. The imaging lens of claim 7 , wherein the following conditional expression is further satisfied:
−1.3< f/f 6<−0.4 (4-1)
where f6 is the focal length of the sixth lens.
14. The imaging lens of claim 13 , wherein the following conditional expression is further satisfied:
−1.2< f/f 6<−0.5 (4-2).
15. The imaging lens of claim 8 , wherein the following conditional expression is further satisfied:
−3.5<( L 4 r+L 4 f )/( L 4 r−L 4 f )<−1.6 (5-1)
where:
L4r is the paraxial radius of curvature of the image side surface of the fourth lens; and
L4f is the paraxial radius of curvature of the object side surface of the fourth lens.
16. An imaging apparatus equipped with the imaging lens of claim 1 .