An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a convex surface on the object side and having a positive power; a second lens having a concave surface on the object side and having a negative power; a third lens having a positive power; and a fourth lens having a convex surface on the object side near a paraxial axis and having a meniscus shape. The imaging lens satisfies conditional expressions specified in the specification.
1. An imaging lens comprising: in order from an object side of the imaging lens,
a first lens having a convex surface on the object side and having a positive power;
a second lens having a concave surface on the object side and having a negative power;
a third lens having a positive power; and
a fourth lens having a convex surface on the object side near a paraxial axis and having a meniscus shape,
wherein the imaging lens satisfies conditional expressions (1) to (5):
0.7 <f 1 /f <1.1 (1)
1.45<n1<1.6 (2)
ν1>60 (3)
0.8 <|f 2 /f 51 <1.8 (4)
1.9 <f 3 /f <20 (5)
wherein
f1 designates a focal length of the first lens;
f designates a total focal length;
n1 designates a refractive index of the first lens at the d-line;
ν1 designates an Abbe number of the first lens at the d-line;
f2 designates a focal length of the second lens; and
f3 designates a focal length of the third lens.
2. The imaging lens according to claim 1 , further satisfying conditional expression (6):
bf/TL >0.2 (6)
wherein
bf designates a distance, on air basis, from an image-side surface of the fourth lens to an image plane; and
TL designates a distance from an object-side surface of the first lens to the image plane.
3. The imaging lens according to claim 1 , further satisfying conditional expression (7):
TL /(2 ×Ih )<1.1 (7)
wherein
Ih designates a maximum image height in an image plane and
TL designates a distance, on air basis, from an object-side surface of the first lens to the image plane.
4. The imaging lens according to claim 1 , wherein each of the second to fourth lenses includes at least one aspheric surface.
5. The imaging lens according to claim 1 , wherein the first lens includes at least one aspheric surface.
6. The imaging lens according to claim 1 , wherein each of the second to fourth lenses is made of a resin material.
7. The imaging lens according to claim 1 , wherein the first lens is made of an optical glass.
8. The imaging lens according to claim 1 , further comprising:
a stop disposed between an object-side surface position on the optical axis in the first lens and an image-side surface position on the optical axis in the first lens.