The invention relates to an optical
system, a
camera module and an electronic device. The optical
system includes, in order from an object side to an image side: a first lens element with refractive power having an object-side surface being convex at an
optical axis and an image-side surface being concave at the
optical axis; a second lens element with refractive power, wherein the object-side surface of the second lens element is convex at the
optical axis; a third lens element with refractive power, wherein the image-side surface of the third lens element is concave at the optical axis; a fourth lens element with positive
refraction power, the object side surface of the fourth lens element being a
concave surface at the optical axis, and the image side surface of the fourth lens elementbeing a convex surface at the optical axis; a fifth lens element with
negative refraction power, the object side surface of the fifth lens element being a convex surface at the optical axis, and the image side surface of the fifth lens element being a
concave surface at the optical axis. The relationship is satisfied: 1 < GLD / f < 5, wherein GLD is the maximum distance from the object side surfaceof the first lens element to the image side surface of the fifth lens element in the direction parallel to the optical axis, and f is the effective
focal length of the optical
system. The optical system not only has the characteristic of
miniaturization, but also can improve the shooting effect on long shot and close shot.