WIDE-ANGLE OPTICAL SYSTEM WITH VARIABLE FOCUS

A fisheye-type wide-angle optical system (1) with variable focus mounted on an electronic image formation system (2) comprising a non-planar electronic image sensor (3) with fixed radius of curvature. The optical system comprises a first group of lenses (A) with negative refractive power and a second group of lenses (B) with positive refractive power moving with respect to each other between a shorter focal distance configuration and a longer focal distance configuration. The optical system satisfies condition (I) where C is the radius of curvature of the image formed by the optical system and bfw is the distance between the end lens of the imaged space of the second group of lenses and the object image formed by the optical system in the shorter focal distance configuration.