Cant focus electronic lenses w/ electronic adapter?

Hey BMC community, I have a pretty serious issue that I cant seem to find an answer for anywhere else. I have the BMCC MFT mount camera and the redrock micro EOS to MFT adapter (http://store.redrockmicro.com/livelensmft). I have a sigma 18-35mm on order, but I wanted to give the camera a try because I hate waiting. So I put my buddies kit lens on the T5i (18-135 f3.5-5.6 http://www.bhphotovideo.com/c/product/945056-REG/canon_8595b005_eos_dig_rebel_t5i.html) on my camera.

the lens wont focus. Aperture works beautifully using the adapter but the focus ring just spins around. Why? Is this with some/most/all electronic lenses? Will the Sigma focus?

The BMCC MFT mount is a "passive" mount -- no power. A number of MFT (i.e Panasonic MFT ) and Canon EOS lenses do not have a real manual focus, rather manual focus on these lenses is done by a "focus by wire" control, where manual focus ring controls the lens' focus motor, which requires power to work.
The new Sigma zoom specs show "manual" focus and a manual/auto focus switch, but it is not clear as if this is a focus by wire, or true manual focus. Sigma lists the focus as:
"Hyper Sonic AF Motor
The Hyper Sonic Motor provides fast, quiet, and smooth auto focusing that is well-suited for use with video applications. This AF motor can also be manually overridden at any time by rotating the focusing ring, giving you the ability to fine-tune image sharpness through manual focusing."

Check Internet reviews to see if anyone makes this clear.

Take heart, the number of Canon EF lenses that focus by wire are extremely limited; can't speak for the ES series. In fact, the such EF lens that I know of is the 85/1.2.