Microsoft today released Lumia Camera Beta update for Some Lumia devices. It is available for Lumia 930, Lumia Icon, Lumia 1520, Lumia 640 and Lumia 640 XL and requires the Lumia Denim update.
Lumia Camera Beta release (v5.21.0.0) includes:Access to Office Lens from settings menu,
Pro settings remembered after restarting the app,General performance improvements and bug fixes
Microsoft will use this app to verify the latest and greatest bug fixes and improvements before they are rolled out in the commercial Lumia Camera app for the same devices.
You can download it here