Imaging lens and imaging apparatus
The imaging lens consists of, in order from an object side: a first lens group G 1 ; a diaphragm; and a second lens group G 2 that has a positive refractive power. The first lens group G 1 consists of, in order from the object side, a first A lens group G 1 A that consists of two negative meniscus lenses concave toward an image side, and a first B lens group G 1 B that consists of only one positive lens or a negative lens and a positive lens. The second lens group G 2 consists of, in order from the object side, a biconvex lens, a biconcave lens, one or two biconvex lenses, and a negative meniscus lens that is concave toward the object side. With such a configuration, the imaging lens satisfies predetermined conditional expressions.
1. An imaging lens consisting of, in order from an object side:
a first lens group;
a diaphragm; and
a second lens group that has a positive refractive power,
wherein the first lens group consists of, in order from the object side, a first A lens group that consists of a first-1 negative meniscus lens concave toward an image side and a first-2 negative meniscus lens concave toward the image side, and a first B lens group that consists of a first-3 positive lens or a first-3A negative lens and a first-3B positive lens,
wherein the second lens group consists of, in order from the object side, a second-1 biconvex lens, a second-2 biconcave lens, a second-3 biconvex lens, and a second-4 negative meniscus lens that is concave toward the object side, or in order from the object side, a second-1 biconvex lens, a second-2 biconcave lens, a second-3A biconvex lens, a second-3B biconvex lens, and a second-4 negative meniscus lens that is concave toward the object side, and
wherein the following conditional expressions (1) and (2) are satisfied,
−1<( L 22 f+L 22 r )/( L 22 f−L 22 r )<0.5 (1), and
−0.6< f 1 A/f 1 B<− 0.25 (2),
where L22f is a radius of curvature of an object side surface of the second-2 biconcave lens,
L22r is a radius of curvature of an image side surface of the second-2 biconcave lens,
f1A is a focal length of the first A lens group, and
f1B is a focal length of the first B lens group.
2. The imaging lens according to claim 1 ,
wherein the following conditional expression (3) is satisfied,
−0.7<( L 23 r−L 240/( L 23 r+L 24 f )<−0.1 (3),
where L23r is a radius of curvature of an image side surface of the second-3 biconvex lens or the second-3B biconvex lens, and
L24f is a radius of curvature of an object side surface of the second-4 negative meniscus lens.
3. The imaging lens according to claim 1 ,
wherein the following conditional expression (4) is satisfied,
−1< f/f 1 A<− 0.4 (4),
where f is a focal length of a whole system.
4. The imaging lens according to claim 1 ,
wherein the following conditional expression (5) is satisfied,
−0.3< f/f 24<0 (5),
where f is the focal length of the whole system, and
f24 is a focal length of the second-4 negative meniscus lens.
5. The imaging lens according to claim 1 ,
wherein the following conditional expression (6) is satisfied,
−1<( L 24 f−L 24 r )/( L 24 f+L 24 r )<−0.2 (6),
where L24f is a radius of curvature of an object side surface of the second-4 negative meniscus lens, and
L24r is a radius of curvature of an image side surface of the second-4 negative meniscus lens.
6. The imaging lens according to claim 1 ,
wherein an air spacing is provided between the second-3 biconvex lens or the second-3B biconvex lens and the second-4 negative meniscus lens.
7. The imaging lens according to claim 1 ,
wherein the following conditional expression (7) is satisfied,
0.2<( L 11 f−L 11 r )/( L 11 f+L 11 r )<0.7 (7),
where L1 if is a radius of curvature of an object side surface of the first-1 negative meniscus lens, and
L11r is a radius of curvature of an image side surface of the first-1 negative meniscus lens.
8. The imaging lens according to claim 1 ,
wherein the first-2 negative meniscus lens is a lens of which object side and image side surfaces are aspheric surfaces and of which a negative refractive power becomes weak in a periphery thereof as compared with a vicinity of an optical axis thereof.
9. The imaging lens according to claim 1 ,
wherein the second-4 negative meniscus lens is a lens of which object side and image side surfaces are aspheric surfaces and of which a negative refractive power becomes weak in a periphery thereof as compared with a vicinity of an optical axis thereof.
10. The imaging lens according to claim 1 ,
wherein the following conditional expression (1-1) is satisfied
−0.8<( L 22 f+L 22 r )/( L 22 f−L 22 r )<0.4 (1-1).
11. The imaging lens according to claim 1 ,
wherein the following conditional expression (2-1) is satisfied
−0.55< f 1 A/f 1 B<− 0.3 (2-1).
12. The imaging lens according to claim 2 ,
wherein the following conditional expression (3-1) is satisfied
−0.6<( L 23 r−L 240/( L 23 r+L 24 f )<−0.15 (3-1).
13. The imaging lens according to claim 3 ,
wherein the following conditional expression (4-1) is satisfied
−0.85< f/f 1 A<− 0.5 (4-1).
14. The imaging lens according to claim 4 ,
wherein the following conditional expression (5-1) is satisfied
−0.23< f/f 24<−0.03 (5-1).
15. The imaging lens according to claim 5 ,
wherein the following conditional expression (6-1) is satisfied
−0.85<( L 24 f−L 24 r )/( L 24 f+L 24 r )<−0.35 (6-1).
16. The imaging lens according to claim 7 ,
wherein the following conditional expression (7-1) is satisfied
0.3<( L 11 f−L 11 r )/( L 11 f+L 11 r )<0.6 (7-1).
17. An imaging apparatus comprising the imaging lens according to claim 1 .