Design of the Compact Optical System for Multiple Focal Length

A compact power spectrum collection lens (PSCL) system is proposed in this paper. The system consists of former lens, later lens and magnifying lens. In this system the former lens of F500 is fixed, the focal length of later lens can be changed to realize the focus-length of F500, F800 and F1000. The former lens component is F500 or F1000, as the later lens component, a magnifying lens of 4 times change focus-length of the system from F500 to F2000 or from F1000 to F4000. The lens barrel length of the optical system is no more than 1020 mm. In this way, the lens barrel length of the whole system is shorter, and it has good image quality. This lens system can be used in those optical systems with various focus length and it can shorten the lens barrel length of the whole system.