An optical photographing lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element with positive refractive power has a convex object-side surface. The second lens element has positive refractive power. The third lens element has negative refractive power. The fourth lens element with refractive power has a convex object-side surface and a concave image-side surface, wherein the surfaces thereof are aspheric. The fifth lens element with positive refractive power has a convex image-side surface, wherein the surfaces thereof are aspheric. The sixth lens element with negative refractive power has a concave image-side surface, wherein the image-side surface changes from concave at a paraxial region thereof to convex at a peripheral region thereof, and the surfaces thereof are aspheric.