Imaging lens and imaging apparatus equipped with the imaging lens
View Patent ↗An imaging lens substantially includes seven lenses, constituted by: a first lens having a positive refractive power and a convex surface toward an image side; a second lens having a negative refractive power; a third lens having a positive refractive power; a fourth lens; a fifth lens having a positive refractive power; a sixth lens; and a seventh lens having a negative refractive power, a concave surface toward an image side, and at least one inflection point in the surface toward the image side; provided in this order from an object side. All of the first lens through the seventh lens are single lenses.
1. An imaging lens substantially consisting of seven lenses, including, ordered as follows from an object side:
a first lens having a positive refractive power and a convex surface toward the object side;
a second lens having a negative refractive power;
a third lens having a positive refractive;
a fourth lens;
a fifth lens having a positive refractive power;
a sixth lens; and
a seventh lens having a negative refractive power, a concave surface toward an image side, and at least one inflection point on the surface toward the image side,
all of the first through seventh lenses being single lenses.
2. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
0< f/f 12 (1)
wherein f is the focal length of the entire system, and f12 is the combined focal length of the first lens and the second lens.
3. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
f/f 2<−0.1 (2)
wherein f is the focal length of the entire system, and f2 is the focal length of the second lens.
4. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
0< f/f 1<2.5 (3)
wherein f is the focal length of the entire system, and f1 is the focal length of the first lens.
5. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
0< f/f 3 (4)
wherein f is the focal length of the entire system, and f3 is the focal length of the third lens.
6. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
f/f 4<0 (5)
wherein f is the focal length of the entire system, and f4 is the focal length of the fourth lens.
7. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
0.08< Da/f (6)
wherein f is the focal length of the entire system, and Da is the thickness of the first lens along the optical axis.
8. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
0.05< Db/f< 0.3 (7)
wherein f is the focal length of the entire system, and Db is the thickness of the second lens along the optical axis.
9. The imaging lens as defined in claim 1 , wherein the following conditional formula is satisfied:
0.2< Dc/f< 0.5 (8)
wherein f is the focal length of the entire system, and Dc is the distance from the surface of the first lens toward the object side to the surface of the second lens toward the image side along the optical axis.
10. The imaging lens as defined in claim 1 , further comprising:
an aperture stop, provided between the first lens and the second lens or between the second lens and the third lens.
11. The imaging lens as defined in claim 2 , wherein the following conditional formula is satisfied:
0< f/f 12<5 (1-1)
wherein f is the focal length of the entire system, and f12 is the combined focal length of the first lens and the second lens.
12. The imaging lens as defined in claim 3 , wherein the following conditional formula is satisfied:
−1< f/f 2<−0.2 (2-1)
wherein f is the focal length of the entire system, and f2 is the focal length of the second lens.
13. The imaging lens as defined in claim 4 , wherein the following conditional formula is satisfied:
0.5< f/f 1<2 (3-1)
wherein f is the focal length of the entire system, and f1 is the focal length of the first lens.
14. The imaging lens as defined in claim 5 , wherein the following conditional formula is satisfied:
0.32< f/f 3<1 (4-1)
wherein f is the focal length of the entire system, and f3 is the focal length of the third lens.
15. The imaging lens as defined in claim 6 , wherein the following conditional formula is satisfied:
−0.65< f/f 4<0 (5-1)
wherein f is the focal length of the entire system, and f4 is the focal length of the fourth lens.
16. The imaging lens as defined in claim 7 , wherein the following conditional formula is satisfied:
0.1< Da/f< 0.3 (6-1)
wherein f is the focal length of the entire system, and Da is the thickness of the first lens along the optical axis.
17. The imaging lens as defined in claim 8 , wherein the following conditional formula is satisfied:
0.06< Db/f< 0.2 (7-1)
wherein f is the focal length of the entire system, and Db is the thickness of the second lens along the optical axis.
18. The imaging lens as defined in claim 9 , wherein the following conditional formula is satisfied:
0.21< Dc/f< 0.4 (8-1)
wherein f is the focal length of the entire system, and Dc is the distance from the surface of the first lens toward the object side to the surface of the second lens toward the image side along the optical axis.
19. The imaging lens as defined in claim 11 , wherein the following conditional formula is satisfied:
0.2< f/f 12<1 (1-2)
wherein f is the focal length of the entire system, and f12 is the combined focal length of the first lens and the second lens.
20. An imaging apparatus, comprising the imaging lens defined in claim 1 .