Buyers' Guide: Lighting Kits
Lighting is the single most important determinant of video quality. Fortunately, the cost of quality lighting gear has plummeted over the last few years. So with a little bit of knowledge, which I’ll supply here, and a very modest budget, you can provide great lighting for your online conferences, webinars, and presentations.
Lighting Theory
There are two factors to consider when buying lighting gear. The first is color temperature. All light bulbs have a color temperature defined on the Kelvin (K) scale (Figure 1, below). These range from “warm” light sources like candles and incandescent bulbs to cooler temperatures typically delivered via fluorescent, compact fluorescent (CFL), or LED lights. If you’re a filmmaker, you might choose a color temperature to set a mood or create an impression. However, if you’re shooting for business use, your primary concern is to make sure that all light sources share the same color temperature. Otherwise, you won’t be able to white-balance effectively, and a portion of your frame could be off-hue.
Figure 1. Color temperatures of common light sources (frostelectric.com/colortemplight)
Fortunately, this shouldn’t be an issue for most producers, because incandescent lighting fixtures with really warm tones are no longer prevalent. Most offices use fluorescent lighting in the 4,000 K–5,600 K range, and as long as you supplement this with bulbs of similar color temperatures, you should be in good shape. As shown in Figure 1, you can buy CFL, fluorescent, and LED bulbs in multiple color temperatures. If you’re buying a light kit to work with existing office lights, identify the color temperature of the bulbs you’ll be matching before you purchase.
Color Rendering Index
The second bulb-related factor is the Color Rendering Index (CRI) score, which measures the ability of an artificial light source to accurately reveal colors in comparison with a natural light source. Higher scores are better than lower ones, with a score of 80 deemed acceptable and 90 considered “high-CRI.”
You can see the impact in Figure 2 (below); as the CRI increases, the colors get more vivid. The bottom line is that whenever you buy a light kit or light bulb, you should track down the CRI score and make sure it’s as high as possible.
Figure 2. The impact of CRI on the vividness of colors (standardpro.com/colours-of-store-merchandise)
Lighting Implements
With these basics in place, let’s look at how affordable lighting has evolved over the years. Back around 2005 or so, most light fixtures were incandescent, like the Lowel Tota Light (now available as an LED) shown in Figure 3 (below). These smallish fixtures used tungsten incandescent bulbs that generated
intense light but also intense heat. Think back to shop lights you might have used during that time period, and you get the idea.
Figure 3. Three generations of lighting implements
Incandescent bulbs have a fixed color temperature that you could only change by applying a gel, essentially a colored piece of thin plastic, over the light fixture. You also typically had to diffuse the light with some kind of material or fixture; otherwise, the light was too strong and harsh. Overall, the power of these lights made them a great light source, but the heat made them very hard to work with. Today, few, if any, light kits use incandescent bulbs.
Next came CFL fixtures, which included a bulb and a softbox to focus the light (see the Alzo Digital Softbox in the middle of Figure 3).These implements were much larger than incandescent fixtures, but generated much less light and, fortunately, much less heat. The softboxes were cumbersome and top-heavy on their stands, so they tended to fall over if accidentally pushed and had to be placed closer to the subject because of the comparatively weak output.
Like incandescent bulbs, CFL bulbs have a fixed color temperature, but the sheer size of the softbox complicated applying gels. The light was also hard to direct because it’s very difficult to apply fixtures like the barn doors shown on the Lowel Tota Light to a softbox. While there still are many kits that use CFL bulbs and softboxes, LED lights are taking over.
Although not as powerful as incandescent, LED lighting fixtures are much smaller than CFL fixtures and more rigid, which simplifies attaching gels and barn doors, if needed. They’re also less cumbersome than softboxes and less easy to tip over.
LED lights all have a single color temperature, but by combining both 3,200 K and 5,600 K bulbs on a single fixture, you can dial in any color temperature between the two by adjusting the relative intensity of the different colored bulbs. That’s why you see both orange and white bulbs in the Genaray Spectro shown on the right in Figure 3. The downside of this approach is that you split the bulb strength and the amount of generated light. That is, if you bought a 500-bulb fixture with a 5,600 K temperature, you would get twice the output of a fixture that mixed 250 3,200 K bulbs and 250 5,600 K bulbs.
With LED lights, the number of bulbs roughly translates to the intensity that each fixture produces. As you’ll see, the lights you’ll consider to boost your webcam image feature 60–70 bulbs, which should be plenty, because the light will be so close to your face. Larger lights for traditional shoots will typically include 480–1,000 bulbs.
With these basics covered, let’s look at the most common lighting scenario for businesses: webcam use for conferencing or webinars.
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