I've been on set the last few days with a TetherBoost Pro USB 3.0 Core Controller. This item is one of TetherTools' newest additions to their tethering lineup and I have to admit, I had some reservations about whether this would work since I've had a lot of trouble getting their regular active USB 3 extension to keep a connection with a Canon 5Ds.
Without getting too technical, it's a known issue that tethering any USB 3 camera to a USB 3 port on an Apple MacBook Pro will inevitably result in a lost connection at some point because Apple stupidly doesn't regulate the power to each of the two USB 3 ports on the MBP. It's really annoying especially when you're trying to shoot a lot with minimal interruption.
But because I've literally tried every other solution under the sun for this issue, I figured trying one more -- even a new one -- wouldn't hurt. I'm happy to report that the TetherBoost Pro USB 3 Core Controller really does work when connecting to a MBP over a 30' distance. Placing this Core Controller between the 15' USB 3 cable from the camera and the TetherTools USB 3 Active Extension going into the computer works quite well and so far, after 2 straight days of shooting, there hasn't been any dropouts. Hurrah! I think the problem has finally been solved.
So if you're having trouble tethering a USB 3 camera to Capture One running on a MacBook Pro, this is the solution you're looking for. Get it here.