Patent ID: 8164678

Claim:
An optical photographing lens assembly comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; a second lens element with negative refractive power having a concave image-side surface; 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 image-side surface on which at least one inflection point is formed, the object-side and image-side surfaces thereof being aspheric; wherein a stop is disposed between an imaged object and the first lens element and an electronic sensor is disposed at an image plane for forming images of the imaged object; wherein the optical photographing lens assembly further comprises another stop disposed between the second lens element and the fourth lens element; and wherein half of a diagonal length of an effective pixel area of the electronic sensor is ImgH, a distance on an optical axis between the another stop disposed between the second lens element and the fourth lens element and the electronic sensor is LS, half of an aperture diameter of the another stop is YS, a distance on the optical axis between the another stop and an object-side surface of a lens element adjacent to and on the object side of the another stop is DS, a distance on the optical axis between the object-side surface of the lens element adjacent to and on the object side of the another stop and an image-side surface of a lens element adjacent to and on the image side of the another stop is DL, a focal length of the optical photographing lens assembly is f, a focal length of the third lens element is f 3 , a focal length of the fourth lens element is f 4 , a distance on the optical axis between an object-side surface of a lens element with refractive power closest to the object side and an image-side surface of a lens element with refractive power closest to the image side is Td, an Abbe number of the first lens element is V 1 , an Abbe number of the second lens element is V 2 , and they satisfy the relations: (ImgH−0.7*LS)/ImgH<YS/ImgH<0.74, 0.10<DS/DL<0.73, 1.35<f/f 3 <2.50, −2.60<f/f 4 <−1.75, 0.85<Td/f<0.92, 20.0<V 1 −V 2 <42.0.