This is the camera app you are looking for

With an iPhone 6 Plus, the replaces and exceeds my old SLR, video/film, and editing suite. You would need several thousand dollars to purchase any marginal increase in quality, negated as soon as Apple admits their phones can record at 4k and, most important, the best camera is the one you have with you. This app means this isnt just by default.

Ghost of a flea about ProCamera. Professional Camera, v6.3