I shoot a lot of video with my iPhone and iPad Pro and I mean a lot. Even some of the stories I've done for us have been shot this way and few people probably could tell the difference.
Cameras on most smartphones are good enough to do some of the things you get with a DSLR; the problem though, is simply holding a mobile device without getting shaky video. That's the problem being solved by "The Padcaster 2", a camera rig for the iPad and soon for the iPhone.
It's basically a cage you snap the device into giving me something sturdy to hold on to. It's weighty but not so much it makes your arm tired but just weighty enough to steady the device more than holding it in your bare hands. The Padcaster has a great feature that mounts a professional camera lens onto the rig right in front of the camera lens. The results improve what you can see and shoot with one of the best cameras on the market.
I used a wideangle lens provided by Padcaster 2 along with a micro lens for closeup shots. I also attached a DSLR lens that worked perfectly. The rig has 13 total holes around it where you can mount other accessories such as lights and a microphone. This further added a pro quality feel to my iPad Pro's camera. I'm impressed. I added a tripod mount to hold those shots steady, (because, you know, shaky video) and it made a big difference while zooming in and out. To shoot the video I used an app Filmic Pro which gave me professional tools such as changing the iris, locking the focus and zooming in smoothly. I'm very impressed and the Padcaster 2, combined with the Filmic app I can see even pro's shooting video and movies. The Padcaster 2 is $189 but combined with microphones, lights, mounts and camera lenses can easily raise the price to more than $400.
Will DSLR shooters switch to an iPad? Some maybe, but when you add the cost of an iPad Pro the total cost might surpass the cost of a Canon 5D Mark III.