There are two ways that you can watch full movie in HD (1080px) .
How to Watch Full HD movies in Amazon Prime?
1.You can watch unlimited movies for free in Amazon Prime for 30 days with free trial.
Click below to sign up for Amazon Prime 30-day Free Trial and Watch unlimited movies and TV Shows.
So you have to Sign up for free to Watch Full movies online privately.
How to Watch Full HD movies in Amazon Video?
You can watch HD movies in Amazon Video renting starting from $4.99. When renting movie, you can have 30 days to start watching this video, and 48 hours to finish once started.