The Leica APO-Tele-Elmar-S 180mm f/3.5 Lens is a superior-quality telephoto characterized by an extremely wide lens opening to enable portraits with a shallow depth of field. This reference-class lens, with special grades of glass and aspherical surfaces, displays consistently high image performance utilizing an inner focusing system with a floating element.It displays maximum performance across the entire image field at all apertures. With a broad effective range of focus (minimum distance of 5-feet), it is possible to produce images at a 1:7 scale. With its special lens elements, vignetting, distortion and chromatic aberrations have been minimized to such a high degree that images don"t require post-production computer enhancement.The APO-Tele-Elmar-S 180mm f/3.5 is equipped with a Leica-designed microprocessor for precise autofocus and iris diaphragm control with silent gearing and it has a focus ring with enough drag to let the user to override the autofocus at any time. ? This lens is designed with special grades of glass and aspherical surfaces. ? S-bayonet mount ensures rapid and precise digital exchange of data and commands between the camera and lens. ? Lens has its own Leica-designed microprocessor for precise autofocus and iris diaphragm control. ? Generous focus ring with just the right amount of drag, letting the photographer override the autofocus at any time. ? The lens is produced to extremely narrow tolerances, with each lens centered by hand, guaranteeing superior quality and optical performance.