We have theoretically proposed a new type of active optical zoom system. It can change the magnification of an imaging system at any field angle, namely, it can change the effective focal length at a limited region of interest and simultaneously maintain high resolution. It is comprised of two static aspheric mirrors and two deformable mirrors; furthermore, by changing the curvature of mirrors the focal length can be adjusted from − 399 to − 558.6 mm. The system reduces the bandwidth of data transmission and may find potential applications in high speed photography. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).Subject terms: any field angle; deformable mirror; active zoom system; optical systems design.Paper 110523RR