Patent ID: 8908289

Claim:
An image capturing lens substantially consisting of a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power, arranged in this order from the object side, wherein: the image side surface of the fifth lens has an aspherical shape with one or more inflection points and a concave shape toward the image side in a paraxial region; and the image capturing lens satisfies the following conditional expressions (1a), (2a), (3a), (5a), and (12b) simultaneously: −1.5 <f/R 2<1.6 (1a); −1.6 <f/R 4<0.05 (2a); 0.95 ≦f 4 /f≦ 4.3 (3a), 1.0 ≦TL/f≦ 2.2 (5a); and −2.0<Σ( fj/νj )/ f< 0.5 (12b), where: f is a focal length of the entire lens system; R2 is a radius of curvature of the image side surface of the first lens; R4 is a radius of curvature of the image side surface of the second lens; f4 is a focal length of the fourth lens; TL is an overall optical length when a distance from the image side surface of the fifth lens to the image plane is represented by an air equivalent length; Σ(fj/νj)/f is [(f1/ν1)+(f2/ν2)+(f3/ν3)+(f4/ν4)+(f5/ν5)]/f; f1 is a focal length of the first lens; f2 is a focal length of the second lens; f3 is a focal length of the third lens; f5 is a focal length of the fifth lens; ν1 is an Abbe number of the first lens; ν2 is an Abbe number of the second lens; ν3 is an Abbe number of the third lens; ν4 is an Abbe number of the fourth lens; and ν5 is an Abbe number of the fifth lens.