Imaging lens
There is provided an imaging lens with high-resolution which realizes the wide field of view, low-profileness, and low F-value in well balance, and proper correction of aberrations. An imaging lens comprising in order from an object side to an image side, a first lens having a convex surface facing the object side near an optical axis and negative refractive power, a second lens having negative refractive power, a third lens, a fourth lens having biconvex shape near the optical axis, and a fifth lens, wherein each lens of the first lens to the fifth lens is arranged without being cemented, and a below conditional expression (1) is satisfied: 0.50< r 5/ r 6<12.50 (1) where r5: curvature radius of the object-side surface of the third lens, and r6: curvature radius of the image-side surface of the third lens.
1. An imaging lens comprising in order from an object side to an image side,
a first lens having a convex surface facing the object side near an optical axis and negative refractive power,
a second lens having negative refractive power,
a third lens,
a fourth lens having biconvex shape near the optical axis, and
a fifth lens having negative refractive power,
wherein each lens of said first lens to said fifth lens is arranged without being cemented, and below conditional expressions (1), (2), (3), and (8) are satisfied:
0.50< r 5/ r 6<12.50 (1)
−35.50< f 2/ f<− 2.75 (2)
−9.00 ≤f 1/ k<− 2.20 (3)
−3.50<( r 9+ r 10)/( r 9− r 10)<13.85 (8)
where
r5: curvature radius of the object-side surface of the third lens,
r6: curvature radius of the image-side surface of the third lens,
f2: focal length of the second lens,
f: focal length of the overall optical system,
f1: focal length of the first lens,
r9: curvature radius of the object-side surface of the fifth lens, and
r10: curvature radius of the image-side surface of the fifth lens.
2. The imaging lens according to claim 1 , wherein a below conditional expression (4) is satisfied:
3.00< r 1/ r 2<6.10 (4)
where
r1: curvature radius of the object-side surface of the first lens, and
r2: curvature radius of the image-side surface of the first lens.
3. The imaging lens according to claim 1 , wherein composite focal length of said first lens and said second lens is negative, and a below conditional expression (5) is satisfied:
−3.20< f 12/ k<− 1.25 (5)
where
f12: composite focal length of the first lens and the second lens, and
f: focal length of the overall optical system.
4. The imaging lens according to claim 1 , wherein a below conditional expression (6) is satisfied:
−3.90< r 7/ r 8<−0.95 (6)
where
r7: curvature radius of the object-side surface of the fourth lens, and
r8: curvature radius of the image-side surface of the fourth lens.
5. The imaging lens according to claim 1 , wherein a below conditional expression (7) is satisfied:
1.00< f 4/ f< 2.85 (7)
where
f4: focal length of the fourth lens, and
f: focal length of the overall optical system.
6. The imaging lens according to claim 1 , wherein a below conditional expression (9) is satisfied:
28.00< vd 4− vd 5<56.00 (9)
where
vd4: abbe number at d-ray of the fourth lens, and
vd5: abbe number at d-ray of the fifth lens.
7. The imaging lens according to claim 1 , wherein a below conditional expression (10) is satisfied:
Fno≤ 2.4 (10)
where
Fno: F-number.
8. An imaging lens comprising in order from an object side to an image side,
a first lens having a convex surface facing the object side near an optical axis and negative refractive power,
a second lens having negative refractive power,
a third lens having a concave surface facing the image side near the optical axis and a meniscus shape,
a fourth lens having biconvex shape near the optical axis, and
a fifth lens having negative refractive power,
wherein each lens of said first lens to said fifth lens is arranged without being cemented, and below conditional expressions (1) and (3) is satisfied:
0.50< r 5/ r 6<12.50 (1)
−9.00 ≤f 1/ k<− 2.20 (3)
where
r5: curvature radius of the object-side surface of the third lens,
r6: curvature radius of the image-side surface of the third lens,
f1: focal length of the first lens, and
f: focal length of the overall optical system.
9. The imaging lens according to claim 8 , wherein composite focal length of said first lens and said second lens is negative, and below conditional expression (5) is satisfied:
−3.20< f 12/ k<− 1.25 (5)
where
f12: composite focal length of the first lens and the second lens, and
f: focal length of the overall optical system.
10. The imaging lens according to claim 8 , wherein a below conditional expression (6) is satisfied:
−3.90< r 7/ r 8<−0.95 (6)
where
r7: curvature radius of the object-side surface of the fourth lens, and
r8: curvature radius of the image-side surface of the fourth lens.
11. The imaging lens according to claim 8 , wherein a below conditional expression (7) is satisfied:
1.00< f 4/ f< 2.85 (7)
where
f4: focal length of the fourth lens, and
f: focal length of the overall optical system.
12. The imaging lens according to claim 8 , wherein a below conditional expression (9) is satisfied:
28.00< vd 4− vd 5<56.00 (9)
where
vd4: abbe number at d-ray of the fourth lens, and
vd5: abbe number at d-ray of the fifth lens.
13. The imaging lens according to claim 1 , wherein a below conditional expression (10) is satisfied:
Fno≤ 2.4 (10)
where
Fno: F-number.
14. An imaging lens comprising in order from an object side to an image side,
a first lens having a convex surface facing the object side near an optical axis and negative refractive power,
a second lens having negative refractive power,
a third lens,
a fourth lens having biconvex shape near the optical axis, and
a fifth lens having a concave surface facing the object side near the optical axis and positive refractive power,
wherein a below conditional expression (1) is satisfied:
0.50< r 5/ r 6<12.50 (1)
where
r5: curvature radius of the object-side surface of the third lens, and
r6: curvature radius of the image-side surface of the third lens.
15. The imaging lens according to claim 14 , wherein each lens from said first lens to said fifth lens is arranged without being cemented.
16. The imaging lens according to claim 1 , wherein a below conditional expression (10) is satisfied:
Fno≤ 2.4 (10)
where Fno: F-number.