drklrd Loc: Cincinnati Ohio

Old flash guns have too high a voltage on their contacts and like has already been said will fry the electronics in a digital camera. You can use a radio flash control that is rated for your Nikon as I do. I use old studio strobes and radio remote them from camera. I experimented until I got the exposures correct using a hand held meter just like the old days. For what I use I have to manually do exposure by meter and set my D7200 on full manual since all the radio does is to fire the flash. The flash units I have are old White Lightnings plus a battery pack unit that is manual. They shot many weddings for me during film days. I am used to setting up studio strobes manually. There are many new flash guns available these days and they are not as expensive as Nikon flash units. In fact if you go Nikon there are Nikon units that will fire a slave flash by radio.

kb6kgx Loc: Simi Valley, CA

I've been using a REAL oldie-but-goodie with my D7100. I've had good results with my Sunpak 555. I just had to buy a hot-shoe adapter so the flash would fire properly. Because its an old flash, it's strictly manual-mode for me. But, it works!