Imaging lens and imaging apparatus
AssigneeNanchang O-Film Optical-Electronic Tech Co., Ltd.
InventorsTaro Asami, Takeshi Kamiya
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Abstract
The imaging lens consists of, in order from an object side, a positive first lens L1, a negative second lens L2, a positive third lens L3, and a positive fourth lens L4. Conditional expressions relating to a focal length f of an entire system, a combined focal length f234 of the second lens L2 to the fourth lens L4, an Abbe number νd1 of the first lens L1, an Abbe number νd2 of the second lens L2, a radius of curvature R1 of a surface of the first lens L1 on the object side, and a radius of curvature R2 of a surface of the first lens L1 on an image side: 0.4<f/f234<2; νd1<50; 5<νd1−νd2<26; −5<(R1+R2)/(R1−R2)<−0.9 are satisfied.
Claims20
An imaging lens consisting of, in order from an object side:
- a first lens having positive refractive power;
- a second lens having negative refractive power;
- a third lens having positive refractive power;
- and
- a fourth lens having positive refractive power,
- wherein all of the following conditional expressions (1) to (4) are satisfied;
- 0.4<f/f234<2 (1)
- νd1<50 (2)
- 5<νd1−νd2<26 (3)
- −5<(R1+R2)/(R1−R2)<−0.9 (4)
- where
- f:
- a focal length of an entire system
- f234:
- a combined focal length of the second lens, the third lens, and the fourth lens
- νd1:
- an Abbe number for d-line of the first lens
- νd2:
- an Abbe number for d-line of the second lens
- R1:
- a radius of curvature of a surface of the first lens on the object side
- R2:
- a radius of curvature of a surface of the first lens on an image side.
The imaging lens according to 1,
- wherein the following conditional expression (6) is satisfied;
- 27<(νd3+νd4)/2−νd2<34 (6)
- where
- νd3:
- an Abbe number for d-line of the third lens
- νd4:
- an Abbe number for d-line of the fourth lens.
The imaging lens according to 2,
- wherein the following conditional expression (6) is satisfied;
- 27<(νd3+νd4)/2−νd2<34 (6)
- where
- νd3:
- an Abbe number for d-line of the third lens
- νd4:
- an Abbe number for d-line of the fourth lens.
The imaging lens according to 3,
- wherein the following conditional expression (6) is satisfied;
- 27<(νd3+νd4)/2−νd2<34 (6)
- where
- νd3:
- an Abbe number for d-line of the third lens
- νd4:
- an Abbe number for d-line of the fourth lens.
The imaging lens according to 4,
- wherein the following conditional expression (6) is satisfied;
- 27<(νd3+νd4)/2−νd2<34 (6)
- where
- νd3:
- an Abbe number for d-line of the third lens
- νd4:
- an Abbe number for d-line of the fourth lens.
Dependencies are inferred from the claim text.