US Patent 10365458 Optical imaging system

An optical imaging system includes 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, sequentially disposed from an object side to an imaging plane. The optical imaging system satisfies the expression BFL/f<0.15, where BFL represents a distance from an image-side surface of the eighth lens to an imaging plane of an image sensor and f represents an overall focal length of the optical imaging system.