I have a D7200 and also several old manual Sunpak hot shoe flashes (before they were called speedlites). I use them with a flash trigger and it works fine as long as I am NOT in manual mode on the camera???? It works (fires the flashes) in A, S, P and even in Custom modes (U1 & U2), but in M the hot shoe does not trigger at all. Is it a setting or do I have a problem? This works fine on my D5200. Thanks for your help.