Abstract: The present disclosure discloses an optical imaging system including, sequentially from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. Each of the first lens to seventh lens has refractive power. An object-side surface of the first lens is concave, and an image-side surface thereof is concave; an object-side surface of the second lens is convex, and an image-side surface thereof is convex; and an object-side surface of the third lens is concave, and an image-side surface thereof is convex. An effective focal length f4 of the fourth lens and a total effective focal length f of the optical imaging system satisfy ?2.0<f4/f<?1.5. Half of a maximal field-of-view Semi-FOV of the optical imaging system satisfies Semi-FOV?55°.

Abstract: The present disclosure discloses an optical imaging system including, sequentially from an object side to an image side along an optical axis, a first lens having refractive power; a second lens having negative refractive power; a third lens having negative refractive power; a fourth lens having refractive power, a convex object-side surface and a concave image-side surface; and a fifth lens having refractive power. A distance TTL along the optical axis from an object-side surface of the first lens to an imaging plane of the optical imaging system and half of a diagonal length ImgH of an effective pixel area on the imaging plane of the optical imaging system satisfy: 1.0<TTL/ImgH<1.5.