Friday, June 1, 2007
Continuous Lights For Digital Shooters
For control and certain effects, many professionals find "hot light" to be the ideal lighting gear
With the prevalence of strobes in the professional marketplace, continuous lights or “hot lights” have fallen out of favor, but they're still excellent tools with some distinct advantages. The term “hot light” actually refers to tungsten, quartz, HMI and halogen lighting equipment as well as newer continuous sources that aren't all that hot to the touch. Although they're all hotter than a strobe setup, technology has made advancements in these lights that has resulted in much cooler units, so that a hot light can be used in some situations where you previously would have shunned them because of the heat.
Why would anyone choose hot lights over strobes? In many cases, it's a personal, indeed, artistic choice. Some photographers simply like the look they get from a continuous source. Strobes are relentless in the way they freeze motion, but with hot lights you can add a little blur and create an image that sometimes seems less sterile, for lack of a better description. Of course, the main advantage of hot lights is that they allow you to see the exact effect you'll get as you make adjustments. Modeling lights on strobe heads give you a decent approximation of how the strobes will look when they fire, but they aren't perfect.
When you adjust a continuous light, the shadows and highlights you see are precisely what you'll get. The instant review capabilities built into digital cameras mitigate this advantage somewhat, but even with the ability to review and adjust a strobe shot, it's still more efficient to use hot lights.
Ask film shooters whether they prefer strobes or continuous lights, and you're likely to get a loud chorus of strobe lovers. That's because one of the main drawbacks of using hot lights with film is the color temperature inherent in the lights. While strobes are usually balanced to daylight (approximately 5200K), most continuous lights are closer to 3200K, which results in a decidedly warm cast. Film shooters got around this cast with tungsten-balanced film or a complex recipe of filters on the camera or lights, or both. Not only was that difficult (you'd be amazed how often your Wratten gels were creased when you went to mount them on your lens), but because the color temperature of the lights and the exact value of the filters could both shift over time, you literally never, ever got it exactly right.
To get the color balance right, you typically needed to have a color meter and a case full of colored gels. In an especially difficult location, it wouldn't be uncommon to gel every light source influencing the set, including a window, fluorescent lights, the main hot-light source and anything else in the room.
So despite many of the advantages of hot lights, you can see how they would have fallen out of favor in a color film-dominated industry. But now, in a digital camera-dominated industry, the problems with color balance melt away for many professionals. Because you can fine-tune the camera's white balance almost with the push of a button, most of the problems of color shift can be quickly remedied.
Beyond the obvious benefits of high power and low cost, hot lights give you creative benefits that strobes don't. The main creative control you get is the ability to convey a sense of motion with a blur. With strobes, any motion is frozen in the strobe's 1/10,000-second duration. This is why strobes are used to capture images of bullets flying through targets. Other than making sure that the whole shutter is open when the strobe goes off, the actual shutter speed becomes largely irrelevant (we're assuming you're shooting with strobe only as opposed to strobes and ambient light).