Abstract: Proposed is a small lens system including a first lens, a second lens, a third lens, and a fourth lens arranged along an optical axis from an object. The iris diaphragm is located between the first lens and the second lens. The first lens has a negative refractive power and includes a surface concave surface on an object side and a convex surface on an image side. The second lens has a positive refractive power and includes convex surfaces on both sides. The third lens has a positive refractive power and includes convex surfaces on both sides. The fourth lens has a negative refractive power and includes concave surfaces on both sides. All surfaces of the first to fourth lenses are aspherical.

Abstract: Disclosed is a small lens system including a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from an object, wherein the clear aperture of an object-side surface L1S1_CA (clear aperture) and the clear aperture of an image-side surface L1S2_CA (clear aperture) of the first lens satisfy 1<L1S2_CA/L1S1_CA<1.2.

Abstract: Disclosed is a small wide-angle lens system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens sequentially arranged from an object, wherein the first lens has a convex object-side surface, the third lens has a negative refractive power, the fourth lens has a concave image-side surface, the sixth lens has a concave object-side surface and a concave image-side surface, the ninth lens has a negative refractive power and a concave object-side surface, all surfaces of the first to ninth lenses are aspherical surfaces, the refractive power P1 of the first lens satisfies |P1|<0.01, and Fno of the lens system satisfies Fno <1.6.