Microsoft has taken up the charge to rename all the apps as a part of Nokia acquisition. The latest addition is the Nokia Camera app which, today got renamed to Lumia Camera, reflecting the post acquisition changes. The app doesn't have any new features but they will come soon as the Denim rollout takes place by the end of this year.
Lumia Camera replaces Nokia Camera, while the Classic version is actually the Nokia Camera Beta. An odd way of doing things, but Classic is targeted for hardware without the Denim firmware update. Both apps are currently sat on version 220.127.116.11 and as touched on above, there aren't any noticeable changes in the two new updates.