Imaging lens system and capturing apparatus
An imaging lens system includes a first lens having positive power, a second lens being a meniscus lens having a convex surface on an object side, a third lens, a fourth lens being a meniscus lens having a concave surface on the object side, and a fifth lens having positive power, the first, second, third, fourth, and fifth lenses being arranged in this order from the object side, in which the first lens is a glass lens; the second, third, and fourth lenses are plastic lenses; and the imaging lens system satisfies a following Conditional Expression (1): 1.25< f 1/ f <1.55 (1) where f is a focal length of the entire lens system and f1 is a focal length of the first lens.
1 . An imaging lens system consisting of a first lens having positive power, a second lens being a meniscus lens having a convex surface on an object side, a third lens, a fourth lens being a meniscus lens having a concave surface on the object side, and a fifth lens having positive power, the first, second, third, fourth, and fifth lenses being arranged in this order from the object side, wherein the first lens is a glass lens,
the second, third, and fourth lenses are plastic lenses, and
the imaging lens system satisfies a following Conditional Expressions (1), (2) and (3):
1.25< f 1/ f< 1.55 (1)
| f/f 2|<0.3 (2); and
f/f 3|<0.3 (3),
where f is a focal length of the entire lens system and f1 is a focal length of the first lens, f2 is a focal length of the second lens, and f3 is a focal length of the third lens.
2 . The imaging lens system according to claim 1 , wherein the imaging lens system satisfies a below-shown Conditional Expression (4):
0.1 <bftol <0.3 (4)
where tol is a total track length of the lens system and bf is a distance between a last lens and a focal plane.
3 . The imaging lens system according to claim 1 , wherein the fifth lens has a convex shape on the object side and its image-side surface has an inflection point.
4 . A capturing apparatus comprising:
the imaging lens system according to claim 1 ; and
a capturing element disposed at a focal point of the imaging lens system.
5 . The imaging lens system according to claim 1 , wherein the third lens is a meniscus lens having a convex surface on an object side.
6 . The imaging lens system according to claim 1 , wherein the second lens has negative power.
7 . The imaging lens system according to claim 1 , wherein the fourth lens has positive power.
8 . The imaging lens system according to claim 1 , wherein the fifth lens is a plastic lens.
9 . The imaging lens system according to claim 1 , wherein an object-side lens surface of the first lens is a convex surface.
10 . The imaging lens system according to claim 1 , wherein an image-side lens surface of the first lens is a concave surface.
11 . The imaging lens system according to claim 1 , wherein an image-side lens surface of the second lens is a concave surface.
12 . The imaging lens system according to claim 1 , wherein an object-side lens surface of the third lens is a convex surface.
13 . The imaging lens system according to claim 1 , wherein an image-side lens surface of the fourth lens is a convex surface.
14 . The imaging lens system according to claim 1 , wherein an image-side lens surface of the fifth lens is a concave surface.
15 . The imaging lens system according to claim 1 , wherein the first lens is a spherical lens.
16 . The imaging lens system according to claim 15 , wherein the second, third, fourth, and fifth lenses are aspherical lenses.
17 . The imaging lens system according to claim 1 , wherein the second, third, fourth, and fifth lenses are aspherical lenses.
18 . The imaging lens system according to claim 1 , wherein an image-side lens surface of the fifth lens has an inflection point and a concave curved part.
19 . The imaging lens system according to claim 1 , wherein the first lens has an Abbe number of less than 30.