The current generation of smartphones enables you to capture high-quality HD and 4K footage that meets the requirements of professional filmmakers. For example, all the supporting review videos that I shoot for Digital Camera World are filmed on an iPhone - see this reviews Performance section for my test of the RØDE Cage.
However to take your video (and audio) production values to the next level you need help from accessories such as a shotgun mic to capture more directional sound and an LED to add fill-light to interviewees. These accessories can be a challenge to mount on a standard smartphone case so you need a grip or a cage with screw threads and cold shoe mounts. Check out our best iPhone camera grips to see a range of ways to turn your iPhone into a professional camera rig.
