I don't know of any import plugin for Lightroom to Photos app. However, it is possible to import from the Photos repository, just not that simple.
Photos.app copies all the photos it manages into a separate repository, called "Photos Library". You will need to use the Finder context method command "Show Package Contents" to see inside the library; in there the folder called "Masters" contains all the originally imported files off your camera / card, organized by year and then by import session number.
Method 1: Drag the folder
This is the simplest method:
- Open Lightroom, and click "Import".
- Switch to Finder.
- Right-click on your Photos library and select "Show Package Contents"
- Drag the "Masters" folder from the Finder to the Lightroom window, dropping it in the big central area of the window (ie, not in or above the folder treeon the left).
- Select which photos you want to import
Of course, with this method you can drag a specific year (or specific import session) over instead of everything if you want to be more selective.
Method 2: Use an Alias
The above method is the simplest, but not most intuitive from the Lightroom interface. In that interface, you see a large folder tree on the left from which you are asked to select a folder. However, navigating to your "Pictures" folder it doesn't allow you to select the Photo Library. This is because OS X stores the Photo Library as a "package", and Lightroom was not coded to be able to look into packages (which is the better default, from a development perspective, unless Lightroom was to look inside only certain types of packages, like the Photos package).
However, like any good OS X denizen, Lightroom will treat an "alias" to a folder just like the folder itself. So, we can get it to see folders inside that package by making aliases outside the package.
- On your Mac, go to your Pictures folder, and look for something called Photos Library.
- Right click on it and choose 'Show Package Contents'. This will open up the repository into a folder view, showing lots of files, and a folder called "Masters". This folder contains all the unedited versions of your Photos in the Photos app. (because Photos is non-destructive, edits are stored outside of the image, just like Lightroom).
Sub-Method 2a: All Masters
- Open a second Finder window (Cmd-N), and navigate in that window to your "Pictures" folder
- Click and drag the "Masters" folder from the one window to the "Pictures" folder window, but do not drop it yet.
- Hold both the "alt/option" key and the "command" key down, so that a little curved arrow appears over the Masters folder you are dragging, and while that overlay icon is showing, release the mouse button. This will create an alias to "Masters" that you can directly import into Lightroom.
Sub-Method 2b: Selecting Specific Years (or import sessions)
- Right-click a folder, say "2014", choose 'Make Alias'. A folder with an arrow will be created just below the "2014" folder.
- Drag this alias folder to your desktop (or some other location), because this alias was created within the hidden Photos repository.
- Do this for every folder you want to import photos from.
To complete Method 2...
- Open Lightroom, and click 'Import'. Navigate to the location where you put all the alias's. These will show as folders to Lightroom, containing all the photos from that year within Photos.app.
- Import away!