Note: This only works with iPhone 7.
Apple has revamped the iPhone’s camera in the 7 models and it now features Hollywood level recording capabilities. You can toggle between different video recording resolutions in Settings under Photos and Camera.
Resolution options start at 720 HD and extend all the way to 4K. Keep in mind that shooting in 4K will drain your phone’s disk space so sticking with standard HD is probably best for everyday recording.