How to set iPhone 6 to record 1920x1080 HD videos?

How to set iPhone 6 to record 1920x1080 HD videos?

Currently my iPhone 6 is recording small 568x320 MOV files. I need 1920x1080

Its set to do that from the start. Just launch the Camera app & use the video function. The only option you could change is whether for it to be 30 or 60fps.

It should be HD by default, mine is.