This telephoto lens is one of Canon's premier offerings. Capable of focusing to life-size without attachments, it is an excellent macro lens. It utilizes a ring type USM, resulting in quiet, high-speed autofocus. The manual focus is smooth and crisp. A long working distance of 149mm means you never have to worry about getting too close to a subject, either. The front ring does not rotate making use of accessories such as macro rings a snap. The lens is designed from three independently moving groups, which keeps focusing-related image changes to a minimum. That means you can expect clear images all the way from macro to life-size, whether you are shooting a subject that is close up or far away. This lens is great for everyone, from the hobbyist to professional.