All disk drives need to be unmounted before they are unplugged. This includes all removable disk drives (including cameras), and network servers.
The same process will eject any disk drive, local, or networked: drag it to the trash.
Note: You don't have to unmount a drive before you unplug it if it doesn't appear on the desktop. All disk drives and most cameras should appear on the desktop, however there are some cameras that do not appear on the desktop and for those, you can just yank them when you're done.