Imaging lens and imaging apparatus including the imaging lens
View Patent ↗An imaging lens substantially consists of, in order from an object side, five lenses of a first lens that has a positive refractive power and has a meniscus shape which is concave toward an image side, a second lens that has a negative refractive power and has a meniscus shape which is concave toward the image side, a third lens that has a negative refractive power and is concave toward the object side, a fourth lens that has a positive refractive power and has a meniscus shape which is convex toward the image side, and a fifth lens that has a biconcave shape and has an aspheric shape which has at least one extreme point on an image side surface. Further, the imaging lens satisfies predetermined conditional expressions.
1. An imaging lens consisting of, in order from an object side, five lenses of:
a first lens that has a positive refractive power and has a meniscus shape which is concave toward an image side;
a second lens that has a negative refractive power and has a meniscus shape which is concave toward the image side;
a third lens that has a negative refractive power and is concave toward the object side;
a fourth lens that has a positive refractive power and has a meniscus shape which is convex toward the image side; and
a fifth lens that has a biconcave shape and has an aspheric shape which has at least one extreme point on an image side surface,
wherein the following conditional expressions (1) and (2) are satisfied:
−2.127< f/f 5<0 (1),
and
−0.573< f/f 3<−0.172 (2),
where
f is a focal length of a whole system,
f 5 is a focal length of the fifth lens, and
f 3 is a focal length of the third lens.
2. The imaging lens, as defined in claim 1 , wherein an image side surface of the third lens has an aspheric shape which has at least one extreme point, an intersection point between the image side surface of the third lens and a principal ray with a maximum angle of view is positioned on the object side of an intersection point between the image side surface of the third lens and an optical axis, and an intersection point between an object side surface of the third lens and the principal ray with the maximum angle of view is positioned on the object side of an intersection point between the object side surface of the third lens and the optical axis.
3. The imaging lens, as defined in claim 1 , wherein the following conditional expression is further satisfied:
| f 2 |<|f 3| 4),
where
f 2 is a focal length of the second lens, and
f 3 is the focal length of the third lens.
4. The imaging lens, as defined in claim 1 , further comprising an aperture stop that is disposed on the object side of an object side surface of the second lens.
5. An imaging apparatus comprising:
the imaging lens, as defined in claim 1 .
6. The imaging lens, as defined in claim 1 , wherein the following conditional expression is further satisfied:
−2.06 <f/f 5<−0.56 (1-1),
where
f is the focal length of the whole system, and
f 5 is the focal length of the fifth lens.
7. The imaging lens, as defined in claim 6 , wherein the following conditional expression is further satisfied:
−2.01 <f/f 5<−1.12 (1-2),
where
f is the focal length of the whole system, and
f 5 is the focal length of the fifth lens.
8. The imaging lens, as defined in claim 1 , wherein the following conditional expression is further satisfied:
−0.419 <f/f 3<−0.182 (2-1),
where
f is the focal length of the whole system, and
f 3 is the focal length of the third lens.
9. The imaging lens, as defined in claim 8 , wherein the following conditional expression is further satisfied:
−0.27 <f/f 3<−0.19 (2-2),
where
f is the focal length of the whole system, and
f 3 is the focal length of the third lens.
10. The imaging lens, as defined in claim 1 , wherein the following conditional expression is further satisfied:
0< f/f 4<3 (3),
where
f is the focal length of the whole system, and
f 4 is a focal length of the fourth lens.
11. The imaging lens, as defined in claim 10 , wherein the following conditional expression is further satisfied:
0.7 <f/f 4<2.5 (3-1),
where
f is the focal length of the whole system, and
f 4 is the focal length of the fourth lens.
12. The imaging lens, as defined in claim 11 , wherein the following conditional expression is further satisfied:
1.4 <f/f 4<2.1 (3-2),
where
f is the focal length of the whole system, and
f 4 is the focal length of the fourth lens.