Hello,
Currently on ebay a nice flighline of Albatros D.V
https://www.ebay.de/itm/226180420526...Bk9SR8yprNr9Yw
If I read correctly D.2320/17 & D.4404/17 nearest the camera. If anyone knows the unit shown that would be helpful.
Somewhat less interestingly the same seller has a photo of MvR with Albatros C.IX 4508/16
https://www.ebay.de/itm/226180395393...UAAOSwAq5mYal6
Regards,
Clint