Imaging lens system with high resolution and compact size

An imaging lens comprising, in the order from the object side to the image side:

• a first lens having a positive refraction power;
• a second lens having a negative refraction power;
• an aperture stop positioned between the first lens and the second lens;
• a third lens having a positive refraction power;
• and
• a fourth lens having negative refraction power,
• wherein the imaging lens satisfies the conditions:
• 1<T/F<1.4;
• R3/F>4;
• and
• S1/S2>3;
• wherein T is the overall length of the imaging lens, F is the focal length of the imaging lens, R3 is the radius of curvature of the object-side surface of the second lens, S1 is the vertical distance from the edge to the center of the image-side surface of the third lens, and S2 is the horizontal distance from the edge to the center of the image-side surface of the third lens.