So I just picked up a D5100 and I am very interested in doing light painting. I have been successful with it for being my first try at it. I had the camera on S-mode with the shutter speed at 30sec. But I would like to know how I can have it last longer than 30sec. I know to put the camera and set it to M mode and scroll it to bulb, but i have to physically hold the button down and if i let go it ends the shot. Can someone help me out with that? I read and re-read the manual but I cant find the answer. I know its probably a easy find but i need help.