I use a Panasonic Lumix FZ100 camara to take full 1080 high definition video. I then load the clips into Premiere 8, edit and write the result to a standard DVD. Is the resulting DVD in high definition? If not, is there any advantage in taking the movie in high definition if the final output will be to a DVD disc? If I record in 1080 HD and then write the output to Blu-Ray will the result be in high definition?
As John T. points out, for true HD, you will want to author and burn a BD (Blu-ray Disc).
Now, many newer BD players will enhance an SD DVD, for playback on an HD TV. They have up-rezzing chips, designed to do a good job of this up-rezzing. I have been surprised at how good my SD DVD-Videos look with such BD players and my large screen TV's. Those chips are wonderful, and do an amazing job - still, the material is not HD, and will pale compared to HD to BD.