Abstract: A microfilm image processing apparatus in which a plurality of zoom lenses having different ranges of magnification are provided for selective use and in which each of the zoom lenses has an associated zoom control gear coaxially disposed aroung the lens to be capable of driving the associated zoom lens for axial movement to vary the effective magnificatio ratio to be achieved by the lens, wherein an angular position detector of, for example, the stroboscopic pickup type is provided in conjunction with the zoom control gear on at least one of the zoom lenses to detect the angular position of each of the zoom lenses and thereby determine the magnification ratios achievable by the individual zoom lenses, and an integral magnification ratio detector is provided in association with the zoom control gear on each of the zoom lenses to detect a particular angular position of the associated zoom control gear, the particular angular position of each zoom lens being such that the zoom lens associated with the gear prov