Pulling the Plug

In order to light that night scene in the field a mile from your house, you'll need a couple hundred 50-foot extension cords, or some other AC power alternatives.

Last month we looked at battery powered camera lights; now let's move those lights away from the camcorders to let you create real lighting designs in the dark and stormy night. Yeah, you could go Hollywood and pull juice from a generator — a 3.5kW Honda will drive six movie lights with ease — but often battery power is more practical, with no long cables and no background put-put-put to complicate your audio. So let's survey some lights, consider power options, and see how to make the very most out of your resources while you're out in the dark.

Flashlights — Yes, Flashlights!

Starting modestly, consider ordinary flashlights. Cheap models won't help much, but premium units like D-cell Maglites throw a respectable amount of light. Most Depot Marts offer even larger units that promise to deliver gazillions of lumens over miles. These handheld automotive spotlights are very bright, fitted with large reflectors for a broader beam pattern, and supplied with automotive 12-volt plugs for recharging in the field. I've seen them for as little as 15 bucks. The Maglite types can also be focused from intense and narrow to soft and wide.

Flashlights do have limitations. Most have no provision for attaching them to light stands (though you can improvise mounts if you're handy that way), and their beam patterns are always irregular. Most importantly, flashlights dim as their batteries get low. This both reduces the light output and changes the color temperature. Even so, you can get fine results with them if you strictly observe two rules:

  • Before each and every use, fit all light units with fresh batteries and new bulbs (this doesn't apply to rechargeable models). That will maximize working life and ensure similar color balance in all lights.
  • Reset camcorder white balance before each shot. (For best results, shine the lights on a white card and fill the frame with it while making the adjustment.)

    If you have only an occasional need for outdoor night lighting, you can put together a three-light kit for under $200, including stands.

    Professional Battery Lights

    The white balance issue goes away when you step up to pro-grade movie lights with their constant, 3,200K halogen lamps; but a bigger benefit is versatility. Professional grade lights (intended primarily for on-camera use) are munchkin versions of house power lights, with all their controls and accessories. For a fuller discussion, consult last month's column on camera lights, but briefly, here are some features to look for in buying these units. Make sure you can vary their light output, either by dimming them or by not using multiple lamps. Sure, that improves lighting control, but it also saves power. Take a tip from the low-power "modeling lights" used by still photographers and set up your lighting designs using the lowest power settings. Then, when you're ready to shoot, turn on full power.

    Make sure that every light has (or accepts) barn doors, filters, and diffusion, for studio-grade control. And see that the lights will attach to standard lightweight light stands. In some cases, you'll need an adapter that, in effect, puts a camera shoe on top of a stand. All professional camera lights can be cabled to stand-alone batteries designed for the purpose. I like block batteries (Starved Electrolyte, a.k.a. Gel-Cell, a.k.a. Lead Acid) because they can do double duty as stand-weights, always important in the breezy outdoors.

    While we're on the subject, make sure you're well-supplied with weights. The collapsible plastic water jugs sold for camping work great, and they usually have a hang-up hook that lets you attach them easily to the light stand legs.

    Fluorescent Lights

    Fluorescent lights mate well to batteries because they put out far more light per watt than halogens. Some are near daylight in their color temperature. Others are balanced for 3,200K indoors white balance. Fluorescent lights do not generally mate nickel cadmium batteries, so you will need the custom power setup described below.

    Tube-type fluorescents are not generally suitable, but today you can buy screw-base "curly" bulbs that fit in standard reflector housings. The popular 26-watt model puts out light comparable to a 150-watt halogen. These lamps are 110 volt AC, so they require an inverter to change the 12-volt battery output.

    On the other hand, Fluorescent fixtures made for trailers and motor homes operate directly on 12 volts and emit a whopping amount of light for their size (around 6 by 12 inches and an inch thick). Thin-lites, a popular brand, can be found on the accessories shelves at any RV dealer. Since they're not movie lights, you'll have to adapt them for the purpose and then set white balance manually to suit their non-standard color temperature.

    Home-Grown Power

    Flashlights carry their own batteries and professional lights are matched to rechargeable blocks (NiMH). To make portable juice for fluorescents, however, will take some ingenuity.

    Start with a wheeled cart proportioned like the folding shopping cart you take with you to the store. To accommodate rough ground, fit it with the biggest wheels you can find — two-wheeled golf club carts are easily adapted. Now, add a deep-cycle RV/marine battery (between 105 and 120 amp hour capacity is a good size range). Unlike car batteries, these specialized units can be repeatedly discharged and recharged without damage. Secure the battery in the wheeled caddy, as close to the ground as possible.

    On a shelf above that, install an automotive battery charger and connect it to the battery. Make sure its circuits will allow the charge to taper off to a trickle when the battery is nearly full. And, if you're running 110 volt fluorescents, a third shelf should carry an inverter matched to your lights (300 watt sustained output should be ample). Of course, this isn't needed for 12-volt units. Finally, since you'll be powering maybe three lights off the same rig, you'll need power cords up to about 25 feet long. If your lights are 12 volts, use thick cords (#14 or even #12 gauge wire) because low voltage power is very susceptible to loss through wire resistance.

    And now the fine print. As you can imagine, putting together a rig like this, with all its connections and non-standard plugs, requires considerable knowledge of electricity.

    Do not attempt this unless you are completely confident in your electrical abilities. Although 12-volt wires are not hazardous, batteries can be, so use the same caution you'd employ in jump-starting your car.

    Lighting Techniques

    Even with professional halogen lamps, three lights are mighty puny for outdoor lighting. To make best use of them, follow these tips:

  • Use existing lighting for backgrounds. Let streetlights, shop lights, and signs define the background, leaving your lights free to use on your subjects.
  • When you do need to pick out a background, slash the light across it at an acute angle. Remember: you're not really lighting the background, but only showing that it's there.
  • Light only a couple of important action points at a time. If subjects move out of the light between these important areas, what the hey: it's night already!
  • Instead of the usual key-plus-fill lighting, try key-plus-rim light instead. The heavier shadows on the fill side will look appropriate and the splash of backlight on subjects' heads and shoulders will help define their outlines in the darkness.

    Good Lighting!

    Contributing Editor Jim Stinson's book, Video: Digital Communication and Production, is just out in a second, updated edition.

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