a picture - taking lens for forming an image of an object image on a solid picture - taking element , comprising in order from the object side : a first lens having a positive refractive power and directing a convex surface toward the object side ; an aperture stop , a second lens having a positive refractive power and a meniscus shape directing a convex surface toward the image side ; and a third lens having a negative refractive power and directing a concave surface toward the image side , wherein the picture - taking lens satisfies the following conditional expression : 0 . 20 & lt ; r1 / f & lt ; 0 . 42 , 0 . 10 & lt ; d2 / f & lt ; 0 . 40 , where r1 is a radius of curvature of the object side surface of the first lens , d2 is an air gap on the axis between the first lens and the second lens , f is a focal length of a whole system of the picture - taking lens .