There are already 2 great answers, I just wanted to add some input that would be totoo much as a comment.
Firstly it highly depends on which iPad you own, the camera in the first 2 generations were "garbage". I think that changed a bit with the iPad 3 and iPad Air.
If the quality of your iPad camera doesn't produce suitable material you can stop right there, a different app won't make it look any better.
If we look at smartphone/tablet cameras in general, they have developed tremendously in the last 3 years and you can shoot very high quality videos with some extra equipment like a tripod and an external mic (usb or for the mic jack, doesn't matter really) plus some lightning equipment.
If you happen to have a rather recent "high-end" phone from last 2 years you might want to opt for that instead of the iPad and then only cut the footage on the iPad if you don't want to do that on a full fledged computer. Generally the camera built into modern phones are quite a bit better than what gets built into tablets as most people don't really use their tablet for making photos or videos, they mostly just use it for the occasional snapshot when they happen to have their tablet in their hands. My totally not fact based guess would be that about 70-80% of all photos today are made with a smartphone, just because we have them on our hands nearly all the time.
I own a Galaxy S4 for example and the videos I make with it during daylight have a quality of some 200-300€ FullHD camcorder from 3-4 years ago, even better I'd say. So I'd definitely say that professional video with smartphone technology is possible today, definitely not on a high-end level but definitely for low cost productions, granting some experience with video and some extra equipment as mentioned before.
And my phone is really just an example from my personal experience, it's not extraordinary, a lot of other phones from other manufactures like Apple or HTC have a very similar quality level. Especially the higher-end Nokia phones feature an absolutely impressive camera nowadays.