An extremely powerful, apochromatically correct telephoto lens, available with or without central shutter and equally suitable for portraits and long-distance shots. Three of the nine lens elements perform the focusing of the lens, for excellent sharpness down to the close-up limit of 1.5 meters, even at full aperture. Special glass types with low dispersion, anomalous partial dispersion and a high index of refraction ensure the exceptional imaging performance of this lens.