I purchased this unit for my MarkII tested it on a few canon autofocus lenses.. it worked as it should but I went to a BMCC 2.5 K weeks later so never used it.

Any questions please let me know!

MANUFACTURERS INFORMATION: 

The Okii FC1 USB Focus Controller connects to a Canon DSLR by USB cable and controls focusing and common camera functions. The unit is compatible with the 1D C, 1D X, 1D Mk IV, 5D Mk III/II, 7D, 6D, 70D, 60D, T5i, T4i, T3i, T2i, and T1i, and with all Canon, Sigma, and Tamron autofocus lenses. Tokina lenses are also compatible, but can experience camera lock ups with the Canon 7D if the focus command rate is set faster than the lens is able to move the internal focus element. Manual focus lenses will not have focus control, but other functions, such as settings changes or video start/stop, will work.

The Controller is handheld and connects into Canon's USB protocol by an A to mini-B cable that can be as short as 6 inches or as long as 80 ft. The small size of the unit and the use of a USB cable connection leaves the camera's HDMI output available and accessible. Also, instead of being used handheld, the unit can alternatively be mounted onto a rig by a 1/4"-20 mount on the back of the enclosure.

The FC1 features 9 buttons and a rotating knob. It uses the autofocus motor in a lens to control focus while recording video or in any Live View modes. It also controls video recording Start/Stop, image capture, digital zoom, autofocus/metering, Live View, ISO, aperture, shutter speed, exposure compensation, and focus zone position while not recording.

Certain characteristics of Canon's USB Protocol make the FC1 perform differently than a mechanical follow focus, and the FC1 user guide helps explain the effects. Okii also backs the FC1 with a 15-day money-back guarantee.