Simulating Window Light
By Christopher Grey
Published by SekonicChristopher Grey explains how to use studio lighting to simulate the look of natural light in a portrait setup.
Photographer Chris Grey is an expert on lighting. He's written seven books on the subject, teaches classes and workshops, and is a strong advocate for precise control in the studio. To see more of his work, or to find his books and DVDs, visit his Web site.
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Unless you're a photographer who just lines people up against a wall in the cafeteria for a newsletter shot, your business is predicated on smoke and mirrors. An executive, for example, never looks as good under the fluorescent lights in the ceiling as he or she will when you add a little of your professional mojo to the scene. We are, after all, problem solvers. When a job demands that people do not look "lit," which is to say they look "natural," there are options we might employ to make the shot look like it was taken in a much more beautiful and perfectly lit location. Here's how to make your studio look like one.
I have it on good authority that the latest rage for models' and performers' headshots is natural light, the look of soft light through a large window (or bank of windows) along the side of the subject. Common room items appear in the background instead of plain walls or seamless paper. These objects are rendered out of focus and unrecognizable, and only exist to add emphasis to the illusion that the image was made in a natural environment, as is, and with non-studio lighting.
The key word in that last paragraph is illusion.
Light is versatile, controlled light even more so. The trick is bending it to your will.
I've created the illusion of direct sunlight in previously published books and articles, but this article will deal with soft window light, and the examples will show how to light your scene in a way that mimics a brightly, but not directly, lit room.
After shooting numerous portraits of this nature, I've come to believe that the shots are most believable if the background is overexposed. It's just a mental thing. I think the viewer will accept a natural look if the background is brighter than the foreground.
My first shot was made with two lights. The key light (a.k.a. "main") was a large softbox. I use a 4x6 softbox, but a medium 3x4 box would work in a similar manner. The light would be more contrasty because the source is smaller. The trick is to aim the softbox into a queen-size white bed sheet hung on a boom arm (you could easily clamp the sheet to two light stands, but you'll probably need sandbags or something to keep the stands from tipping to the middle). The size of your softbox will determine the distance from the sheet, about three feet in my case, and is important because you will want the light from the softbox to fill the area of the sheet. This effectively creates an even larger softbox than you started with, because the sheet has become the front line for the light.
I set up a white bookend almost directly in front of the model. I'd left a little space between the edge of the sheet and the bookend so that a little light from the softbox would fall directly upon the bookend, shooting a little more undiluted light from the source onto the bookend, and bouncing it to the model.
An additional white bookend was set to camera right. This bookend reflected light from both the sheet and the other bookend, effectively illuminating and encircling the model with varying degrees of soft light.
Since my model wasn't due for half an hour, I sat on a stool in the spot where I wanted her to be. I took a light meter reading, moving the bookends in closer to me until the light from the key was only 1/3 stop brighter than the reflection. It took a little work, but was worth it, and now I had my working aperture.
I set up a second light, a medium softbox on a boom, and aimed it toward the background. I powered this light to be two stops brighter than the key. Here's a look at the setup:
My first result, below, is quite nice. Well-lit with circular light, it looks genuine, and blows out the background so it looks like it's actually been bathed in strong light.
One thing I would change for this first example is that I don't like the vertical catchlight in the camera-right side of the model's eyes. I think her camera-right eye shows too much of a straight vertical reflection. It makes me think I should take a can of black spray paint and place a semi-circular pattern along the edge and angled toward the center. This would allow more pupil and iris color to be represented. The downside of this is that the actual light strength of the bounce would be slightly diminished. It's your call.
Another option is to create two large, soft lights, one from a softbox aimed into the queen-size sheet and another from a light aimed at a seamless white background, bounced toward the subject.
I set my sheet and softbox to the model's left, my camera-right. With the model in position, I moved the light until I liked the way it fell across her face. One thing you have to watch for is how the light falls across the nose. One of the signatures of window light is that it falls broadly over a wide area. It still produces a shadow that must be worked with compositionally to produce a beautiful image. If the shadow is upwardly directed it will not be as attractive, so place the softbox as high as possible as it angles to the sheet. The result will be much more attractive "natural" light.
My model was positioned about four feet from a typical white seamless paper background. I placed a strobe, fitted with a beauty bowl (a basic parabolic would work but might be more contrasty because the source is smaller) at the end of the sweep, angling it to bounce from the background to the model.
I measured each light individually, powering the shadow-side light 2/3 stop below the key. I set the camera's aperture between the two readings, giving me an exposure that was 1/3 stop below target for the shadow and 1/3 stop above target for the highlight. In other words, if the highlight measured f/10 and the shadow side measured f/13, the camera would be set at f/11. You can do this the traditional way, measuring each light to within a 1/3 stop tolerance, but the wraparound spread from the sheet would add more light to the shadow side and probably skew the reading. I counted on the extra spread adding more brightness to the minus side, knowing that even if the light had an accurate shadow-to-highlight ratio it would still be attractive. Play with this yourself and you'll understand it quickly.
An additional medium softbox was set to camera-right and behind the model, aimed at the background and powered one stop over the key. Here's the setup:
The final result from this scenario is both lovely and authentic:
When you're creating shots like these, use the longest lens you have at the largest aperture possible, to guarantee the least depth of field. Use neutral density gels over the lens or lights if necessary to get the desired depth of field. Also, angle the background light to mimic the key (the highlight) whenever possible, just to keep the light spread consistent. Doing so will make your images more believable.