#5. "RE: Manual lens on D90 and built in flash will not fire r 18 error?" In response to In response to 4
All of the Nikon Speedlights SB-600, SB-700, SB-800, SB-900, and SB-910 (SB-400 can only be set in Manual though certain camera bodies)) can be set in Manual flash mode and will work when using non CPU (MF) lenses. Good Luck and Enjoy your Nikons!