This is a medium telephoto macro lens for EF-S lens-compatible EOS digital SLR cameras. It has an angle of view approximately equivalent to a 96mm lens in the 35mm format, and is capable of macro photography up to life size(1:1). With an optical design utilizing the advantages of the short back focus and smaller image circle of the Advanced Photo System C size imaging element, the lens achieves life-size macro photography together with lightweight compactness. Its lightweight, compact design makes it perfect for nature photography. The optical system of twelve elements in eight groups uses only environmentally friendly lead-free glass,and has inner focusing by the third grouop. It gives high image quality throughout the entire focusing range and a 90mm working distance, the longest in its class for life-size photography. Since the length of the lens does not change when focusing, there is no concern about the end of the lens touching the subject when focusing, allowing you to get even closer. The optical design and coating are optimized to reduce the flare and ghosts that are prone to occur with digital cameras. The quick and quiet inner focusing and ring-type USM autofocusing ensure that exclusive photo opportunities are not missed when shooting insects and small animals. The lens mechanism is designed to ensure that it fits only EOS DIGITAL SLR cameras designd to take EF-S lenses. It is equipped with a special attachment indicator and protective rubber mount ring to prevent mistaken attempts to attach it to other EOS SLR cameras, and to prevent damage to the camera body.