Last time around, we showed how backlighting can define the shape of a portrait subject —or any opaque object—by etching a bright white highlight, called a rimlight, around its outer edges. But it has other uses, too, as Christoph Seiler, 37, a research scientist from Philadelphia, discovered when he tried it out with translucent subjects.
“I made this picture last winter,” says Seiler. “It was gray and wet outside, and I was craving bright spring colors. I picked up a handful of yellow spider mums and experimented with inexpensive shoe-mount strobes to find a setup that worked for them. I quickly discovered that backlighting really brought out their color.”
It also brought an unusual, spiky edge to what’s clearly not a conventional floral study.
Aiming a light through a translucent subject and toward the camera has its problems, though. Flare, for one, reduces contrast and color saturation. “To keep the backlights out of the camera’s lens, I narrowed the flashes’ output with snoots that I made from black aluminum foil,” Seiler explains. “And I changed the position, power, and aim of the three backlights until the mums’ color was intense and flare was not. It took about 2 hours and dozens of trial-and-error shots.”
As for exposure, Seiler set his strobes to manual. “That gave me a consistent and adjustable lighting. I started by setting an aperture that would throw the background flowers out of focus and create a sense of depth. Then I manually set the output of each light independently, and finally fine-tuned exposure by adjusting ISO.”
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He started with small halogen lights, which let him analyze lighting effects without the time-consuming requirement of instantaneous-flash test shots. The problem? The heat generated by hot lights placed close enough to shine through the flowers quickly wilted them. Using flash was more practical.
(A) To accentuate the yellow in three spider mums, Christoph Seiler used backlighting from two Sunpak Auto 422D flashes and a Vivitar 285HV flash.
(B) The flashes were mounted on two Cullmann 3090 tabletop tripods and a single Joby Gorillapod.
(C) Seiler focused the output of each flash with snoots he made from BlackWrap, black aluminum foil.
(D) To preserve detail in the centers of the flowers, he frontlit them with low-power manual pop from a tripod-mounted Metz 48 AF-1.
(E) He fired all four strobes wirelessly from the camera position using an inexpensive, eBay-sourced PT-04 radio-slave-based flash triggering system consisting of a transmitter and receivers (not shown) on the four flash units. He processed the images in Adobe Lightroom 3.