compensation by means of only one movement or by means of only linearly related movements, e.g. optical compensation

Full Title

Optical objectives with means for varying the magnification (anamorphotic objectives G02B13/08) > by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective > compensation by means of only one movement or by means of only linearly related movements, e.g. optical compensation