The autofocus capability is very impressive on the Canon 70d. However you can't just wave the camera around and expect it to know where you want to focus - or not. The Servo AF touch screen function is very useful so you can control when to turn AF on or off. This helps when reframing and in many other ways as well.

My question - Is there a way to program a button to turn Servo AF on and off rather than using the touchscreen function? There are some shooting situations where this would be very useful such as when shooting outdoors with a hood on the LCD. I haven't been able to find it on the camera but I am hoping it's there and I missed it.

Months late, but check the Custom Controls menu as described on page 383 of the instruction manual. There might be a way to do it.

Thanks Chris, I found an alternate way that works well. I turn the AF off on-screen and then use the AF-ON button on the back of the camera to turn AF on as needed. This mode focuses and locks. It doesn't continuously focus but that mode is what I want. To refocus, the AF-ON button needs to be depressed again.