Buying lights may not be as exciting as buying a new camcorder, but the impact on your images can be equally significant. In this Buyer's Guide, we'll review the important things you should consider when investing in a lighting package.
The hardness of a light generally refers to its size in relation to the subject. A six-inch spotlight placed 25 feet from your talent will create a shadow with a sharply-defined edge. That same six-inch spot only two feet away from a small piece of jewelry will have a softer edge, since it is now relatively large in relation to the subject. That's the physics. But for our discussion of various lighting fixtures, soft lights will include soft boxes, and hard lights will include spots, small floods, focusable fixtures and any lights that use Fresnel lenses.
Soft boxes are a staple for most video producers, because they cast a pleasing light on just about any subject that's easy to position and nearly impossible to mess up. The problem is that they scatter light like marbles tossed down a spiral staircase. Using a grid or eggcrate will help wrangle those stray photons, but they can add significant cost to a lighting fixture. Some manufacturers include a recessed front panel or even removable flaps to help give a bit more directionality to the light. The interior surface can be either white or silver, and some designs incorporate an internal diffusion panel to reduce the hotspot in the center. Be sure you don't use a lamp that exceeds the maximum wattage, and always allow the soft box to vent as recommended by the manufacturer.
Getting the most from hard light sources takes a little more time to master. Many videographers start with open-faced floods and focusable spot/floods. The floods are a great way to bring up the general light level of a scene, while the spots can serve as a main light, either unaltered for strong shadows or diffused for a softer edge. These lights can even do double-duty as soft lights when bounced into umbrellas or off walls of other reflectors. While more expensive, Fresnels provide much more lighting control than open-faced designs, even when used in a flood setting. They also have a smoother transition from the center of the light beam to the edge.
Using tungsten lamps is one of the least energy efficient way to produce light. Tungsten's inefficiency means you'll have to balance your power load more carefully in older homes and questionable electrical set-ups. It also means the lights themselves will get very hot even just minutes after turning them on. They are, however, among the most popular, because there is such a great variety of lamp wattages and lighting fixtures that use them. They can be found in open-faced spots, floods, focusable spot/floods, Fresnels and soft boxes. The color temperature ranges between 2800 and 3400 degrees Kelvin. If you shoot interior scenes that use standard household lamps as props or even fill light, the lower color temperatures blend well with standard light bulbs.
Three other lamp types are much better at producing more light than heat. They are fluorescents, LEDs and HMIs. Fluorescents require slightly more complex circuitry and ballast and are much larger than standard tungsten fixtures. They are excellent for shooting in an office where you will be balancing with existing light. They also generate very little heat, so you can turn them off and pack them away almost immediately. There are several new color temperature fluorescent lamps now on the market, so be careful when balancing with your shooting environment. LEDs are becoming popular for on-camera applications. They are light, draw very little power and have a lamp life measured in thousands of hours. Their output is limited, but they are great for fill light when you are close to your subject. HMIs, or Hydrargyrum Medium Arc-length Iodide, are the kings of cool and efficient light. They have nearly five times the light output of tungstens at the same power draw, and the lamps last hundreds of hours, sometimes thousands depending on the particular lamp. Some newer designs have come down in price, but most remain very expensive.
Just how much light will you need? If you will be lighting mostly interiors, one way to figure this out is to ask yourself three questions. How many light sources will it take to create the style you want? How close, on average, will your main (key) light be from your subject? And how much of the image do you want in focus?
Your answer to the first question is the most critical. One well-placed and well-chosen instrument can produce impressive results, when carefully balanced with available light. However, a good starting point is usually three lights.
How close you will be from your subject will guide you in choosing the light output of your main, or key, light. The closer you are, the less light output you'll need at the same camcorder aperture. While there are many appropriate ways to measure light, such as foot-candles, lux, luminance and lumens, watts is not one of them. Unfortunately, manufacturers don't use any one measurement type consistently, so, for tungsten lamps, you will usually see wattage listed as the only comparison of light output. This does not take into account lamp efficiency or how the lighting fixture alters the intensity.
How much of an area you want in focus, your depth of field, will tell you what aperture or f-stop you'll want to set on your camcorder. If you want lots of depth, it's simple...you'll need lots of watts.
Mods and Money
Anything you put between or even near the lamp and the subject modifies the quality of your light. This includes reflectors, grids, barn doors, umbrellas, scrims, cookies, gels, etc., and it can be work just figuring out which ones you really need. Many beginning videographers find that umbrellas, color correcting gels and diffusionmaterial are all they need to meet most of their lighting challenges. As you begin to develop an eye for what you don't want to light, you will need more ways to control the light spill.
Investing in a reliable lighting kit can be costly, but, unlike most other gear, it won't become obsolete any time soon. To get a sense of the overall cost and value to your type of videography, you need to add together three factors: the initial cost of the lighting fixture, the power draw and the lamp replacement cost. Don't forget about considering other usage factors, such as durability, weight, size, breakdown and cool-down times. If you have multiple interviews scheduled for the same day in different locations, all of these become critically important. And yes, those inexpensive halogen lights you can find at any hardware store will work as floods in a pinch. Just don't expect your clients to be impressed.
Contributing editor Brian Peterson from Videomaker.Com