Abstract: An optical device (20) that comprises at least two refractive optical elements (1, 2) arranged along an optical axis (OA) of the device, each refractive optical element having a surface profile. The device has an optical aperture common to the at least two refractive optical elements and wherein at least one refractive optical element is arranged to rotate relative to another refractive optical element around a rotation axis which intersects the aperture of the device. The device has a plurality of configurations, each configuration having a predetermined optical property, such as the focal length, over at least a first region of the aperture; the configurations being selected by rotating the at least one refractive optical element arranged to rotate. The total area of the first regions divided by the total area of the aperture is a function of the surface profiles of the at least two refractive optical elements.