To transfer both your RAW and modified photos from your MacBook to an external backup drive, you can follow these steps:
- Open Photos from the Dock.
- In the Library, select all RAW images you want to move.
- Click File on the top menu bar.
- Select Export > Export Unmodified Originals > Eport.
- In the pop-up Finder window, select the backup hard drive under Locations and then click Export Originals.
To keep your pictures in the Photos library, open the Photos app on your Mac, click Photos on the menu bar > Preferences > General, then check the box next to "Copy items to the Photos library."