This stand alone autofocus lens turns any Olympus OM manual focus camera into an autofocus unit. By pressing the buttons on the side of this lens the built in CCD sensor, microchip and focus motor are activated to detect focus anomalities and correct focus when necessary. The electronics and AF motor are powered by three AAA size batteries in the built-in battery compartment. In combination with the OM-30 (OM-F) this lens turns into a dedicated unit that can also be controlled by the shutter release button. With a Winder or Motor Drive, any OM body, and the M.In-Focus Trigger Cord, Single or Continuous In-Focus Operation can be achieved: the Winder or Motor Drive will fire when (Single AF) or as long as (Continuous AF) correct focus is detected. This lens has also a normal focusing ring for manual focus; alternatively a Power Focus mode can be selected to control the focus mechanism with two buttons. Extremely rare!