The Prolock EF has electrical contacts to allow powered control over the iris in 1/3rd stop increments via keys on the mount. The mount adapter also provides power to IS stabilization and internal focus servos. When used with the Optitek Optitron Lens Controller, precision repeatable remote focus control is also available.
The Optitek Prolock EF draws its power directly from the camera mount, so no additional cable is required.
The Optitek Prolock EF also features a PL-style clamping lock ring on the Canon EF mount, assuring that the lens will not shift in the lens mount