Imaging lens and imaging apparatus
View Patent ↗An imaging lens substantially consists of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side. When a curvature radius of an object-side surface of the fourth lens is R8, and a curvature radius of an image-side surface of the fourth lens is R9, and an Abbe number of the material of the third lens for d-line is νd3, and an Abbe number of the material of the fifth lens for d-line is νd5, the following conditional formulas (1) and (6) are satisfied: −0.61<( R 8+ R 9)/( R 8− R 9)<0.44 (1); and 38.1<ν d 3+ν d 5<45.1 (6).
1. An imaging lens substantially consisting of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side,
wherein the following conditional formulas (1) and (6) are satisfied:
−0.11<( R 8 +R 9)/( R 8 −R 9)<0.44 (1); and
38.1 <νd 3 +νd 5<45.1 (6), where
R8: a curvature radius of an object-side surface of fourth lens,
R9: a curvature radius of an image-side surface of fourth lens,
νd3: an Abbe number of the material of third lens for d-line, and
νd5: an Abbe number of the material of fifth lens for d-line.
2. An imaging lens substantially consisting of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side,
wherein Abbe numbers of materials of the first lens, the second lens, the fourth lens and the sixth lens for d-line are greater than or equal to 40, and
wherein the following conditional formulas (1-1) and (12) are satisfied:
−0.11<( R 8 +R 9)/( R 8 −R 9) (1-1); and
R 9 /f<− 2.9 (12), where
R8: a curvature radius of an object-side surface of fourth lens,
R9: a curvature radius of an image-side surface of fourth lens, and
f: a focal length of an entire system.
3. An imaging lens substantially consisting of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side,
wherein Abbe numbers of materials of the first lens, the second lens, the fourth lens and the sixth lens for d-line are greater than or equal to 40, and
wherein the following conditional formulas (1-2) and (4) are satisfied:
−0.075<( R 8 +R 9)/( R 8 −R 9)<0.11 (1-2); and
−1.04<( R 10 +R 1)/( R 10 −R 11)<−0.34 (4), where
R8: a curvature radius of an object-side surface of fourth lens,
R9: a curvature radius of an image-side surface of fourth lens,
R10: a curvature radius of an object-side surface of fifth lens, and
R11: a curvature radius of an image-side surface of fifth lens.
4. An imaging lens substantially consisting of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side,
wherein an object-side surface of the third lens is concave, and
wherein Abbe numbers of materials of the first lens, the second lens, the fourth lens and the sixth lens for d-line are greater than or equal to 40, and
wherein νd1/νd3 is greater than or equal to 1.4 and less than or equal to 2.5 when the Abbe number of the material of the first lens for d-line is |d1 and an Abbe number of the material of the third lens for d-line is νd3, and
wherein the following conditional formulas (1-3) and (4-1) are satisfied:
( R 8 +R 9)/( R 8 −R 9)<0.17 (1-3); and
( R 10 +R 11)/( R 10 −R 11)<−0.35 (4-1), where
R8: a curvature radius of an object-side surface of fourth lens,
R9: a curvature radius of an image-side surface of fourth lens,
R10: a curvature radius of an object-side surface of fifth lens, and
R11: a curvature radius of an image-side surface of fifth lens.
5. The imaging lens, as defined in claim 4 ,
wherein the fourth lens is a biconvex lens, and
wherein the fifth lens is a biconcave lens, and
wherein the following conditional formulas (1-3) and (4-1) are satisfied:
( R 8 +R 9)/( R 8 −R 9)<0.17 (1-3); and
( R 10 +R 11)/( R 10 −R 11)<−0.35 (4-1), where
R8: a curvature radius of an object-side surface of fourth lens,
R9: a curvature radius of an image-side surface of fourth lens,
R10: a curvature radius of an object-side surface of fifth lens, and
R11: a curvature radius of an image-side surface of fifth lens.
6. The imaging lens, as defined in claim 1 , wherein the following conditional formula (19) is satisfied:
1<( D 4 +D 5)/f<6 (19), where
D4: an air space between the second lens and the third lens on an optical axis,
D5: a center thickness of the third lens, and
f: a focal length of an entire system.
7. The imaging lens, as defined in claim 6 , wherein the following conditional formula (19-3) is satisfied:
1.9<( D 4 +D 5)/ f< 4.4 (19-3), where
D4: an air space between the second lens and the third lens on an optical axis,
D5: a center thickness of the third lens, and
f: a focal length of an entire system.
8. The imaging lens, as defined in claim 1 , wherein the following conditional formula (20) is satisfied:
−1 <f/R 5<1 (20), where
f: a focal length of an entire system, and
R5: a curvature radius of an object-side surface of the third lens.
9. The imaging lens, as defined in claim 8 , wherein the following conditional formula (20-2) is satisfied:
−0.5 <f/R 5<0.5 (20-2), where
f: a focal length of an entire system, and
R5: a curvature radius of an object-side surface of the third lens.
10. The imaging lens, as defined in claim 1 , wherein the following conditional formula (21) is satisfied:
−3 <f/R 3<3 (21), where
f: a focal length of an entire system, and
R3: a curvature radius of an object-side surface of the second lens.
11. The imaging lens, as defined in claim 10 , wherein the following conditional formula (21-2) is satisfied:
−2.0 <f/R 3<1.5 (21-2), where
f: a focal length of an entire system, and
R3: a curvature radius of an object-side surface of the second lens.
12. The imaging lens, as defined in claim 1 , wherein the following conditional formula (22) is satisfied:
−30 <f 23 /f<− 3 (22), where
f23: a combined focal length of the second lens and the third lens, and
f: a focal length of an entire system.
13. The imaging lens, as defined in claim 12 , wherein the following conditional formula (22-2) is satisfied:
−20 <f 23 /f<− 5 (22-2), where
f23: a combined focal length of the second lens and the third lens, and
f: a focal length of an entire system.
14. The imaging lens, as defined in claim 1 , wherein the following conditional formula (23) is satisfied:
2 <f 45 /f< 25 (23), where
f45: a combined focal length of the fourth lens and the fifth lens, and
f: a focal length of an entire system.
15. The imaging lens, as defined in claim 14 , wherein the following conditional formula (23-2) is satisfied:
4 <f 45 /f< 20 (23-2), where
f45: a combined focal length of the fourth lens and the fifth lens, and
f: a focal length of an entire system.
16. The imaging lens, as defined in claim 1 , where a stop is arranged between the third lens and the fourth lens.
17. An imaging apparatus comprising:
the imaging lens, as defined in claim 1 , mounted thereon.