Small lens system including eight lenses of −+−+−++− refractive powers

Disclosed is a small lens system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, wherein the first lens has a lens surface convex toward an object, the second lens has a lens surface convex toward the object, the third lens has a lens surface convex toward the object, the fourth lens has a positive refractive power, the fifth lens has a negative refractive power, the sixth lens has a lens surface convex toward an image, the seventh lens has a positive refractive power and is configured such that a lens surface is convex toward the object in the vicinity of an optical axis, and the eighth lens has a negative refractive power and is configured such that an object-side surface and an image-side surface are concave in the vicinity of the optical axis.