Tuesday, August 10, 2010
Continuous Lights For Still & Video
As you explore the possibilities of shooting video with DSLRs to augment your still work, a different kind of lighting solution might be in order
We’ve been doing a lot on video since the first DSLRs that could shoot HD video exploded onto the scene. What might have been dismissed as a marketing fad has blossomed into a full-fledged phenomenon. The first video shot with a Canon EOS 5D Mark II, Vincent Laforet’s Reverie, became so popular that it crashed websites where it was hosted. Professional photographers sat up and took notice. These cameras now give us the ability to add video to our projects and our pitches without having to use a separate camera. And, of course, the quality of the video image is incredibly good, which is why these DSLRs have seen use on major feature films and TV shows.
The camera is just one part of the whole equation, of course. When it comes to lighting, still photographers have quickly realized that they need a different solution than strobes. Today, there are a lot of options beyond tungsten for continuous. Fluorescent, halogen, LED, HMI, HID—all of these make up the new alphabet soup of lighting. All are ideal for video work, and they can do the job for still shooting, as well.
k5600 Joker-Bug 400
Back in the day, most photographers selected strobes as their primary sources of lighting because strobes offered a lot of output in a compact package. They also gave us the ability to freeze a subject because the very short duration of the flash burst eliminated any motion blur in the subject. You could mix ambient light with strobes to create an effect—essentially, motion blurs—but that was a creative choice.
Continuous lights (which used to be referred to as “hot lights” because they were very hot to the touch), did not offer the same power-to-size ratio of strobes, and they could be difficult to work with because of the heat. Attaching modifiers wasn’t an easy task, and generally speaking, the lights were just more challenging to use. But hot lights did have some key advantages. They were essentially WYSIWYG (what you see is what you get). Even with modeling lights, it’s not easy to predict exactly how strobes will render a scene until you actually shoot it.
Despite their drawbacks, some still photographers have always favored continuous lights for their still work. These lights do have a different quality than strobes, which often can be described as harsh or cold. Continuous lights tend to give a scene a softness and a warmth that you just don’t get with strobes. It’s not a matter of adding gels and using softboxes and reflectors. There’s just something indefinably different about continuous lights.
HMI lights are in the category called high-intensity discharge (HID) lights. They work with a combination of gas and metal salts, and when an electric charge is applied, an electric arc is created between a pair of internal electrodes. The arc is the light we see. This system is fundamentally different from tungsten lights, which have a metal filament between two electrodes. The filament glows and emits the light when electricity is applied. To work, HMI lights incorporate an electronic ballast. The ballast essentially powers the unit to create and regulate the arc. The system offers a lot of output and it does so quite efficiently. HMI lights in the 200-watt range can generate similar output levels as 800-watt tungsten bulbs.
Because of the power output of HMI lights, they’re ideal choices to use outdoors during daylight. HMIs can give you the necessary power to rival the sun and craft a look. When you start with high output, you can add all sorts of modifiers without losing all of your light.
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