Imaging lens and imaging apparatus
View Patent ↗Disclosed is an imaging lens having a small F number, a wide angle of view, and a low manufacturing cost and capable of obtaining a high-quality image. An imaging lens includes a first lens having a negative power and including a concave surface facing an image side, a second lens having a positive power, an aperture diaphragm, a third lens having a negative power, an aperture diaphragm, a fourth lens having a positive power, a fifth lens having a positive power and including a convex surface facing the image side, and a sixth lens having a negative power arranged in this order from an object side. When the curvature radius of an image-side surface of the third lens is R 3 r and the curvature radius of an object-side surface of the fourth lens is R 4 f , the imaging lens satisfies the following Conditional expression: | R 3 r/R 4 f |<1.0.
1. An imaging lens comprising:
a first lens that is made of glass, has a negative power and includes a concave surface facing an image side;
a second lens having a positive power;
a third lens having a negative power;
a fourth lens having a positive power;
a fifth lens that has a positive power and includes a convex surface facing the image side;
a sixth lens having a negative power; and
a stop positioned in rear of the second lens or the third lens,
wherein the first to sixth lenses are arranged in this order from an object side, and
when the curvature radius of an image-side surface of the third lens is R 3 r and the curvature radius of an object-side surface of the fourth lens is R 4 f , the imaging lens satisfies the following conditional expression:
| R 3 r/R 4 f|< 1.0;
wherein the Abbe number of the fourth lens with respect to the d-line is equal to or greater than 35,
the Abbe number of the fifth lens with respect to the d-line is equal to or greater than 35, and
the Abbe number of the sixth lens with respect to the d-line is equal to or less than 30.
2. The imaging lens according to claim 1 ,
wherein the third lens is a biconcave lens.
3. The imaging lens according to claim 1 ,
wherein, when the focal length of the entire lens system is f and a composite focal length from the third lens to the sixth lens is f 3456 , the imaging lens satisfies the following conditional expression:
f 3456 /f> 0.8.
4. The imaging lens according to claim 1 ,
wherein, when the focal length of the entire lens system is f and the focal length of the fifth lens is f 5 , the imaging lens satisfies the following conditional expression:
0.6 <f 5 /f< 1.2.
5. The imaging lens according to claim 1 ,
wherein, when the focal length of the entire lens system is f and the focal length of the sixth lens is f 6 , the imaging lens satisfies the following conditional expression:
−2.0 <f 6 /f<− 0.6.
6. The imaging lens according to claim 1 ,
wherein, when the focal length of the entire lens system is f and the focal length of the third lens is f 3 , the imaging lens satisfies the following conditional expression:
−1.5 <f 3 /f<− 0.5.
7. The imaging lens according to claim 1 ,
wherein, when the focal length of the entire lens system is f and the curvature radius of an image-side surface of the fourth lens is R 9 , the imaging lens satisfies the following conditional expression:
−1.2 <R 9 /f<− 0.5.
8. The imaging lens according to claim 1 ,
wherein, when the focal length of the fourth lens is f 4 and the focal length of the fifth lens is f 5 , the imaging lens satisfies the following conditional expression:
0.5 <f 4/ f 5<1.5.
9. The imaging lens according to claim 1 ,
wherein the Abbe number of the second lens with respect to the d-line is greater than 32.
10. The imaging lens according to claim 1 ,
wherein the Abbe number of the first lens with respect to the d-line is equal to or greater than 40.
11. An imaging apparatus comprising the imaging lens according to claim 1 .
12. The imaging lens according to claim 1 , wherein
| R 3 r/R 4 f 1<0.9.
13. The imaging lens according to claim 1 , wherein
the first lens has a meniscus shape in which a concave surface faces the image side.
14. An imaging lens comprising:
a first lens that has a negative power and includes a concave surface facing an image side;
a second lens having a positive power;
a third lens having a negative power;
a fourth lens having a positive power;
a fifth lens that has a positive power and includes a convex surface facing the image side;
a sixth lens having a negative power; and
a stop positioned in rear of the second lens or the third lens,
wherein the first to sixth lenses are arranged in this order from an object side, and
each of the lenses is a single lens;
wherein the Abbe number of the fourth lens with respect to the d-line is equal to or greater than 35,
the Abbe number of the fifth lens with respect to the d-line is equal to or greater than 35, and
the Abbe number of the sixth lens with respect to the d-line is equal to or less than 30.
15. An imaging lens consisting of:
a first lens that is made of glass, has a negative power and includes a concave surface facing an image side;
a second lens having a positive power;
a third lens having a negative power;
a fourth lens having a positive power;
a fifth lens that has a positive power and includes a convex surface facing the image side;
a sixth lens having a negative power and including a concave surface facing the object side; and
a stop positioned in rear of the second lens or the third lens,
wherein the first to sixth lenses are arranged in this order from an object side, and
when the curvature radius of an image-side surface of the third lens is R 3 r and the curvature radius of an object-side surface of the fourth lens is R 4 f , the imaging lens satisfies the following conditional expression:
| R 3 r/R 4 f|< 1.0.
16. An imaging lens consisting of:
a first lens that has a negative power and includes a concave surface facing an image side;
a second lens having a positive power;
a third lens having a negative power;
a fourth lens having a positive power;
a fifth lens that has a positive power and includes a convex surface facing the image side;
a sixth lens having a negative power and including a concave surface facing the object side; and
a stop positioned in rear of the second lens or the third lens,
wherein the first to sixth lenses are arranged in this order from an object side, and
each of the lenses is a single lens.