| CPC G02B 13/0045 (2013.01) [G02B 9/64 (2013.01)] | 9 Claims |

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1. An imaging lens system comprising eight lens elements, the eight lens elements being, in order from an object side to an image side along an optical path, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, and each of the eight lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;
wherein the object-side surface of the third lens element is concave in a paraxial region thereof; and the fifth lens element has negative refractive power;
wherein a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, a curvature radius of the object-side surface of the third lens element is R5, a curvature radius of the object-side surface of the fourth lens element is R7, a curvature radius of the image-side surface of the fifth lens element is R10, a central thickness of the third lens element is CT3, a focal length of the imaging lens system is f, a focal length of the fifth lens element is f5, an axial distance between the first lens element and the second lens element is T12, and the following conditions are satisfied:
(R3+R4)/(R3−R4)<0.90;
(R7+R10)/(R7−R10)<0.85;
0.26<CT3/f<2.20;
−1.60<f/f5<0.00;
f/R5<−0.20; and
0.30<T12/f<1.15.
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