Optical Lens System for Taking Image

An optical lens system for taking image comprising, in order from the object side to the image side:

• a first lens element with positive refractive power;
• an aperture stop;
• a second lens element with negative refractive power;
• a third lens element with positive refractive power having a concave object-side surface and a convex image-side surface;
• and
• a fourth lens element with negative refractive power having a concave object-side surface, an image-side surface of the fourth lens element being aspheric, inflection points being formed on the image-side surface of the fourth lens element, in the optical lens system for taking image, the number of lens elements with refractive power being limited to four.

An optical lens system for taking image comprising, in order from the object side to the image side:

• a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface;
• an aperture stop;
• a plastic second lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the object-side surface and the image-side surface of the second lens element being aspheric;
• a plastic third lens element with positive refractive power having a concave object-side surface and a convex image-side surface, the object-side surface and the image-side surface of the third lens element being aspheric;
• and
• a plastic fourth lens element with negative refractive power having a concave object-side surface and a concave image-side surface, the object-side surface and the image-side surface of the fourth lens element being aspheric, inflection points being formed on the image-side surface of the fourth lens element, a distance from the aperture stop to an image plane being SL, a total track length of the optical lens system for taking image being TTL, they satisfying the relation:
• SL/TTL<0.92.
• in the optical lens system for taking image, the number of lens elements with refractive power being limited to four.