Image lens system, image capturing device and electronic device

The invention discloses an image lens system which sequentially comprises a first lens to an eighth lens from an object side to an image side along an optical path. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof. The second lens element has an object-side surface being convex in a paraxial region thereof. The fifth lens element has positive refractive power. The sixth lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof. The seventh lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. The eighth lens element has negative refractive power. The object-side surface or the image-side surface of at least one lens in the image lens system has at least one critical point at an off-axis position. When specific conditions are met, the image lens system grou