I`m trying to do a self portrait with a long exposure. What I want to do is be in complete black, set the camera to bulb, shoot at an empty chair for a few-ish seconds, then go and sit on the chair for a few seconds while a flash hits me, then move off the chair, then end the shot. I think this would give a ghosting effect. But the one problem is having the flash go off when I`m sitting in the chair. Is there such a thing as a flash cable, or wireless flash trigger? I`ve searched the internet, but can`t come up with much.