Imaging lens
An imaging lens includes a first lens group that includes sequentially from an object side, a first lens formed of resin and having a positive refractive power and a second lens formed of resin and having a negative refractive power, the first lens and the second lens collectively forming a cemented lens having a positive refractive power. The imaging lens further includes a second lens group that includes a negative lens having a convex surface directed toward an image plane and a third lens group that includes a positive lens, where the first lens group, the second lens group, and the third lens groups are sequentially arranged from the object side.
1. An imaging lens comprising:
a first lens group that includes sequentially from an object side, a first lens formed of resin and having a positive refractive power and a second lens formed of resin and having a negative refractive power, the first lens and the second lens collectively forming a cemented lens having a positive refractive power;
a second lens group that includes a negative lens;
a third lens group that includes a positive lens, wherein the first lens group, the second lens group, and the third lens group are sequentially arranged from the object side,
wherein a condition:
0.5 <f 1 /f <1.0
is satisfied, where f 1 represents a focal length of the first lens group and f represents a focal length of the imaging lens.
2. The imaging lens according to claim 1 , wherein conditions:
0.3 <|f 11 /f 12 |<1.0;
and
0 <n 2 −n 1
are satisfied, where f 11 represents a focal length of the first lens of the first lens group, f 12 represents a focal length of the second lens of the first lens group, n 1 represents a refractive index at a d-line of the first lens of the first lens group, and n 2 represents a refractive index at a d-line of the second lens of the first lens group.
3. The imaging lens according to claim 1 , wherein a condition:
OP/ 2 Y <2.0
is satisfied, where OP represents an overall length of the imaging lens, and 2Y represents a diameter of an effective image circle of the imaging lens.
4. The imaging lens according to claim 1 , wherein at least one lens surface is aspherical.
5. The imaging lens according to claim 1 , wherein a lens formed of resin is used for the second lens group.
6. The imaging lens according to claim 1 , wherein a lens formed of resin is used for the third lens group.
7. An imaging lens comprising:
a first lens group that includes sequentially from an object side, a first lens formed of resin and having a positive refractive power and a second lens formed of resin and having a negative refractive power, the first lens and the second lens collectively forming a cemented lens having a positive refractive power;
a second lens group that includes a negative lens;
a third lens group that includes a positive lens, wherein the first lens group, the second lens group, and the third lens group are sequentially arranged from the object side,
wherein conditions:
0.3 <|f 11 /f 12 |<1.0; and
0 <n 2 −n 1
are satisfied, where f 11 represents a focal length of the first lens of the first lens group, f 12 represents a focal length of the second lens of the first lens group, n 1 represents a refractive index at a d-line of the first lens of the first lens group, and n 2 represents a refractive index at a d-line of the second lens of the first lens group.
8. An imaging lens comprising:
a first lens group that includes sequentially from an object side, a first lens formed of resin and having a positive refractive power and a second lens formed of resin and having a negative refractive power, the first lens and the second lens collectively forming a cemented lens having a positive refractive power;
a second lens group that includes a negative lens;
a third lens group that includes a positive lens, wherein the first lens group, the second lens group, and the third lens group are sequentially arranged from the object side,
wherein a condition:
OP/ 2 Y <2.0
is satisfied, where OP represents an overall length of the imaging lens, and 2Y represents a diameter of an effective image circle of the imaging lens.