A zoom lens for a copying system capable of both magnification and reduction of the image of an original to be copied in which the overall lens system may be miniaturized but yet various aberrations such as distortion are well corrected for. The lens includes a first lens group having a negative focal length and a second lens group having a positive focal length disposed in that order from the object side of the lens system. The distance between the first and second lens groups is variable while the distance between the object surface and the image surface is maintained constant. Movement of the first lens group serves primarily to maintain constant the distance between the object and image surfaces while the movement of the second lens group serves mainly to provide a variator effect.
