Karl,
Yes to #1 -- you can even change the camera settings remotely (e.g. adjust aperture, shutter speed, ISO, etc.) so the camera really just needs to be set up on a tripod, boom, mast, etc. As smartphones don't really have a concept of half-pressing a button, Canon has two buttons (small and large) to represent half-press and full-press so you can still pre-focus a shot.)
As for #2 -- that depends on network mode and obstructions. In "infrastructure" mode, both the camera and mobile device will join the same existing WiFi network. But the camera can also create it's own wireless network (e.g. you could be miles from the nearest wifi network and the camera will create it's own WiFi network that the phone can join.) If you do the latter, then it's a matter of obstructions. Unlike Bluetooth where distance is limited to perhaps 30 feet, WiFi can go for hundreds of feet. The actual distance will depend on if the camera and mobile device have "line of sight" or if there are obstructions in the way.
As for #3 -- the camera kicks into "live view" mode when being remotely controlled by the mobile device but you can turn live-view on or off remotely to conserve power. The camera sleep time can be controlled by camera menus, but cannot be controlled by the EOS remote app. So you'd have to preset that.
You can find out more about the remote app here: http://www.usa.canon.com/cusa/consumer/standard_display/EOS_app
(Important note: This only works for Canon models with built-in WiFi such as the 6D and 70D.)
You can see a YouTube video that walks you through how it all works here: http://www.youtube.com/watch?v=D4dY_msd94A
Regards,
Tim
Tim Campbell
5D III, 5D IV, 60Da
