Imaging lens

An imaging lens which forms an image of an object on a solid-state image sensor, in which elements are arranged in order from an object side to an image side, comprising:

• a first lens as a meniscus lens having a convex surface on the object side;
• a second lens;
• a third lens having a convex surface on the image side;
• a fourth lens having, a concave surface on the object side;
• and
• a fifth lens;
• wherein an F-value is 2.5 or less, and conditional expressions (4a) and (6) below are satisfied:
• 0.5<f1/f<0.9 (4a)
• 1.5<r4/f<=2.3 (6)
• where
• f:
• focal length of an overall optical system of the imaging lens
• f1:
• focal length of the first lens
• r4:
• curvature radius of the image-side surface of the second lens.

An imaging lens which forms an image of an object on a solid-state image sensor, in which elements are arranged in order from an object side to an image side, comprising:

• a first lens having a convex surface on the image side;
• a second lens having a concave surface on the image side;
• a third lens having a concave surface on the image side and negative refractive power;
• a fourth lens;
• and
• a fifth lens having a convex surface on the object side;
• wherein an F-value is 2.5 or less, and a conditional expression (3) below is satisfied:
• 0<νd3−νd4<40 (3)
• where
• νd3:
• Abbe number of the third lens at d-my
• νd4:
• Abbe number of the fourth lens at d-ray.

An imaging lens which forms an image of an object on a solid-state image sensor, in which elements are arranged in order from an object side to an image side, comprising:

• a first lens having a convex surface on the image side;
• a second lens having a concave surface on the image side;
• a third lens having a concave surface on the image side and negative refractive power;
• a fourth lens;
• and
• a fifth lens;
• wherein an F-value is 2.5 or less, and conditional expressions (3) and (5b) below are satisfied:
• 0<νd3−νd4<40 (3)
• −1.42≦f2345/f≦−0.76 (5b)
• where
• νd3:
• Abbe number of the third lens at d-ray
• νd4:
• Abbe number of the fourth lens at d-ray
• f:
• focal length of an overall optical system of the imaging lens
• f2345:
• composite focal length of the second lens, the third lens, the fourth lens, and the fifth lens.