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Rangefinder
Magazine Lighting for Digital in the Studio by Claude
Jodoin This article will try to eliminate the myths and clear up the confusion that exists on the subjects of light ratios and fill flash, particularly where digital imaging is concerned. With negatives, no amount of overexposure could ever make up for a bad ratio. For digital, it’s even simpler: Overexposure is Death! No one can help you unless you want someone to paint back in the delicate diffuse highlights you have destroyed in the process (e.g., Bridal gowns, white tops). So, if you make a mistake, make sure it’s underexposure. You can usually save that in Photoshop!
Traditionally, “acceptable” light ratios for portraiture have been anywhere from 2:1 through 8:1; the most popular being 3:1, with 8:1 reserved for dark, dramatic shadows, the use of heavy diffusion, or true “soft-focus” lenses. For digital capture, I prefer 2:1 ratios, softboxes, sharp lenses and custom white balance with a Wallace Expo-Disc (no digital photographer should be without this tool). Since
most studios today use softboxes and have white walls, the fill comes
from the wraparound light and the high ambient efficiency, so there
is less power required than in the past when a camera-axis fill light
is used (for greater consistency). The fill light always accumulates
on the diffuse highlight side to shift the exposure. Stay tuned for how
much… We must trigger and meter each light separately, so an assistant is useful. Flat incident diffuser attachments require a more precise aim, so don’t waste the money unless you do copy work. Important: always point the dome at the light source for one light, and at the camera for both lights.
The table (left) will translate the full range of traditional ratios along with precise meter readings for their achievement. As you can see, when the ratios reach 5:1 or higher, exposure compensation becomes negligible. This same table can apply for different working apertures also. It is easiest to use the “minus so many stops” numbers in parentheses, and this author prefers to use the “minus” methods for both reflector and flash fill. Just remember that the flash fill versus reflector fill requires two distinctly different metering methods and sets of “minus so many stops” tables. For those who might resist all of this stuff, remember that this is the age of digital technology. We have precise, affordable metering instruments (to within 1/10 stop) at our disposal. Let’s learn how to use them, develop habitual discipline, and make overexposed files a thing of the past. Eliminating the possibility of overexposure will enable us to concentrate fully on the creative aspects of photography, without worry (what we get paid for). Digital cameras are sensitive to 1/10-stop variations. If you control this before you click the shutter, you will not have to touch your files at all later on. Time is money, and it’s better spent before than after. I have millions of perfectly exposed files to prove it.
These days, “fixed” fill flash in the studio is typically done with a large light source directly over and behind the camera about 10–20 feet away, depending on the size or layout of the camera room. To create this type of light source, the light from the flash head can be bounced from a white ceiling, large, flat, back wall; large umbrella, or through a large light box. This makes for a more “hassle-free” setup and works well for large groups or individual portraits. In this situation, we generally have a fixed distance for the fill lights, which means we can only vary ratios by changing the relative intensity with the power setting on the fill flash controls. I prefer Paul C. Buff monolights because for digital capture, their slider controls are essential. Since we are creating large fill sources, farther away, the power requirements tend to be greater for the fill than for the main. Use a lower powered monohead for the main since it is usually closer. I recommend Alien Bees 400s, as some terrific, affordable lights for digital capture, since we need less power than for medium format film capture.
However, we can simplify this even further. On the practical side, if a photographer wants a constant shooting aperture of f/8, for consistent depth of field, background appearance, etc., the chart below might be even more helpful than the one on pg. 40. For a 3:1 (competition ratio), the main light should read f/5.6.5 and the fill light should read f/4.0.5. The combined reading would then read the desired f/8.0. For a 2:1 ratio (kid-tested, mother-approved), both lights should read f/5.6.0 for a camera setting of f/8.0. These numbers, of course, assume that the photographer has determined a personal Exposure Index for each different digital camera used in the studio. The ratio methods are still good regardless, but for the overall exposures to be “right on,” meter calibration is an absolute necessity. No shortcuts, no compromises! Here’s a
simplified method that requires only two meter readings (and an assistant)!
We will use the highlighted 3:1 ratio as an example
(1:3 ratio if you’re Dean Collins). Claude Jodoin has been involved in digital imaging since 1986 and has not used film since 1999. He is an event specialist, as well as shooting numerous weddings and portrait sessions throughout the year. You can e-mail him at: claudej1@aol.com. Captions: 1. Camera: Prism Foveon ISO 32, Raw file processed in Foveon Lab to TIF, to PSD, to JPEG. Lens: Canon L f/2.8 28–70mm Exposure: 1/60 f/5.6; meter: Minolta Flashmeter V on subject’s right cheek. All 5 light sources are White Lighting X series. A Chimera 3x4 softbox was feathered toward a large 9x9’ fill flat to serve as main exposure on the face. The back/hair separation light was a normal head bounced off a 16-foot ceiling to read f/5.6. Twin rim lights standard heads (7” parabolics) were feathered toward the black velvet cloth behind the subject to outline subject and background. The camera was custom gray-balanced from the main light on a Kodak 18% gray card near the face. All retouching, soft focus was done in Photoshop 7 using a Wacom 6x8 tablet. 2. Camera Fuji S2 Pro, ISO 100, 50mm f/1.4 Nikkor lens; Exposure: 1/125 @ f/5.6. Minolta V reading of f/5.6 on subject’s left cheek. Lit by twin White Lighting X series. Box on right was a 3x4 foot Chimera, box on left, Larson 14”x48” strip light, reading f/4.0.5. All retouching, soft focus in Photoshop 7 using Wacom 6x8 tablet. 3. Camera: Prism Foveon ISO 32, Raw file processed in Foveon Lab to TIF, to PSD, to JPEG. Lens: Canon L 28-70mm. Exposure: 1/60 @ f/5.6. Meter: Minolta Flashmeter V on subject’s left cheek. All 3 light sources are White Lighting X series. The Chimera 2x3 softbox was feathered across the subject and down toward a fill reflector below, which was retouched out of the eyes. The back/hair separation light was a normal head bounced off a 16-foot ceiling to read f/5.6. A second softbox, reading f/4.0 created the soft rim light in the shadow area. Dark vignetting, retouching, and selected softening were performed in Photoshop 7.0 using Wacom 6x8 Tablet.
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