Lighting: Night Lighting

Robert G. Nulph, Ph.D.
March 2008

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What do you do about lighting, if the only time you get to shoot is at night? What about shooting night scenes - how do you light them to look realistic yet still be able to record a good image? Night lighting can be tricky, but when you get it right, the end result can be awesome! In this column, we will look at the basics of f-stops and lighting and how you can use that knowledge to create realistic and very dramatic lighting at night. We will also talk about shooting interiors and making it look like it is a gorgeous moonlit night.

Most camera lenses have a mechanical way to control the amount of light that passes through the lens. The opening in the lens is the aperture, and the iris is the mechanical device that opens and closes to let in more or less light. This works much the same way as your eye. The aperture is the pupil and the iris controls the size of the pupil/aperture. The f-stop is the number that designates the ratio of the overall size of the lens to the size of the aperture or opening, or, in mathematical terms, the focal length of the lens divided by the diameter of the lens opening or aperture: f=F/D. The really interesting thing about the f-stop is that, if you increase or decrease the f-stop by 1 stop, you double the amount of light or cut it in half respectively. Therefore, an f-stop of 5.6 allows in twice as much light as an f-stop of 8 and one-half as much light as an f-stop of 4.

Why is this important? It also affects the depth of field, or the depth of the area that is in focus in front of the camera. If you want to be able to see everything in sharp focus, you need to be able to shoot at a higher f-stop, which means you need a lot more light.

Just having more light does not mean the scene will be brighter. By closing the aperture, you are increasing the depth of field and decreasing the amount of light getting through the lens, thus making it seem darker. When you are shooting a well-lit night scene, it may seem really bright to your eye, but to the camera that is shooting with a high f-stop, there will be beautiful contrast between the bright spots and the dark spots in the scene - the ultimate goal of night shooting.

A way to test your ability to do this is to shoot a scene in a room with white walls. When you set your lights up, place them 60 degrees above your subject and make sure that no light spills on the background. This is called cameo lighting. Close the iris on your camera, so that the skin tones on your talent's face are natural. Use an extra monitor to check your shot. You should end up with a well-lit face and nothing in the background but black. Even in a white walled room! To your eye, the room will seem bright, but, to the camera set to the right exposure for your talent's skin tones, the background will disappear! Ahhh, the power of the f-stop.

As with any kind of lighting setup, especially when doing narrative productions, you have to analyze the scene and determine the look you want. Are you shooting in an alley or a brightly-lit street? Are you shooting in a dark room at night with only street light dribbling through the windows? One thing to remember about light at night: it always has a hard edge. This means you need to use intense smaller lights that create the shadows that make a night scene so compelling. Put away the silks and diffusers. Hard is the only way to go at night, unless you want to add a touch of fill reflected from diffused surfaces.

Once you have identified the setting, then you work to recreate the look of that setting. Some may think that all you need to do with today's equipment is just go out and shoot in the natural available light. While there is nothing stopping you from doing so, the end result will be a real disappointment. Even today's very light-sensitive cameras will produce an image that has a shallow depth of field and a gray, grainy look, if the lighting is not right.

Begin your setup by determining the primary light source and the size of the shot you will need. If you are shooting primarily closeups and medium shots, your lights can be small and close to your subject. However, if you are shooting long or wide shots, you will need to place your lighting instruments in such a way that you do not see them or cannot tell that they are supplementing the light sources you can see. A streetlight, while very bright to our eyes in a dark night, really doesn't produce much light, so you will need to supplement it to create the look you need. Let's take a look at a close and distant setup.

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