How to reduce light flickering in Nikon D5100?

I make stopmotion animations, but they are the same thing as time-lapse videos. I use a Nikon D5100, but the thing is in each picture, the light flickers. Having light flicker degrades the quality of the animation, so is it possible to keep the lighting the same? I know it is the camera because I film at night, curtains drawn, door close, and all lights off except a desk lamp.

Are you using M mode to keep your exposure settings constant? If you use a semi-automatic mode like A or S, a little bit of change in the scene can make the meter choose a slightly different setting.

What he/she ^ said. Don't change the light source at all, and put the camera in full manual exposure mode. Also, if your desk lamp has an incandescent bulb, swap it out for a florescent. Incandescent lamps can flicker, which is usually too fast for your eyes to see, but the camera can.

The camera will flash a light to focus in the dark. This is called autofocus assist. The camera needs enough light on the subject in order to focus on it. Autofocus Assist is an option you can shut off.

If the camera can't focus without the assist, try this. Give it enough light to focus (turn on overhead lights or whatever), focus, shut off autofocus, get back to the light you want, shoot.