http://www.nikonchat.com/nikon-3100-manual-focus/

I'll take photos at a club event, what type of lens should I use?
My friend asked me to take pictures at a club or party you are pulling. Is that my first shoot for something like this. I'm an amateur photographer with a Nikon d/3100 and kit lens. The only goal I have is the 50mm f1.8 lens manual focus. I was thinking about using the 50mm lens because I think better shooting in low light. Or my stock lens do?
Add a SB600 flash and flash diffuser and should be adjusted. If you have no dedicated external flash, you can buy a Gary Fong "balloon" and use their cameras internal flash. The "stock" 18-55 mm lens will give you much more flexibility than the 50 mm medium telephoto lens, especially when the filming of "group" shots
Nikon D3100 Manual focus test