This is one of the most popular lenses, having a long history as a standard lens. This early model had a metal lens to body ring as opposed to plastic on later models. Compact and lightweight lens with orthodox 6 elements in 5 groups. High image quality with a good balance of aberration correction is obtained throughout the entire focusing range from the closest focusing distance of 0.45m to infinity. Micro-motor operated AF system. This lens was improved to become the model II by simplifying the focusing distance window and manual focus ring.