Digital SLR Photography

How to balance ambient and flash for backlit portraits

By Caroline Schmidt. Posted

With the winter months come glorious vivid sunsets at a far more reasonable hour than we see in summer. Golden-hour sunlight is the best quality of light for almost every subject matter; the sun’s low position, its warmth and softness caresses subjects with an even, beautiful glow, which makes it a fabulous backlight and even backdrop. Unfortunately, photographing a backlit subject against a vibrant sky usually results in one of two things: it renders them as silhouette or the background as overexposed, losing you that arresting colour that made you want to shoot a backlit portrait in the first place. In this tutorial, you’ll be shown how to use flash to balance the exposure for perfectly-exposed skin tones and a sun-kissed sky.

1 Location

Pick an open space with the horizon visible to give yourself the most amount of time and the fewest background distractions. Making sure there are no buildings in the way can gift you more time. Semi-bare trees are useful for creating dappled sunlight and bokeh as well as blocking the sun’s orb to avoid flare. As the sun is low in the sky most of the day, you can generally shoot this type of portrait from 3pm.

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2 Positioning

Where you place your subject in relation to the sun can make a world of difference to how you approach exposing
your subject. Position them against a dark background with the sky out of frame and you’ll likely get a balanced exposure using multi-zone metering and positive exposure compensation; position them with the sun in the frame and you’ll get a wash of light and flare.

3 Exposure

To learn how your camera handles backlit exposures, dial in a wide aperture in aperture-priority mode and multi-zone metering and take a shot – the camera will average the exposure to 18% grey and underexpose the subject. Next, switch to spot metering to expose for the skin tones – this brightens the image but loses background colour and you still need light to fill in facial shadows.

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4 Use flash

Set up your flashgun off-camera for dynamic lighting or keep it on-camera for speed and ease. Here you can see what happens when you leave your camera to work out the exposure. In aperture-priority mode, spot metering and the flash set to iTTL, the system does a great job of filling in the shadows but fails to preserve the best of the background. You need to take control of your exposure.

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5 Manual exposure

Set your camera to manual mode, dial in your preferred aperture and a low ISO. Your shutter speed controls the ambient light when using flash, so find a speed that underexposes the background to retain the glorious colour – here that’s 1/200sec. Remember you cannot set more than your flash sync speed – unless you’ve a High-Speed Sync facility – check the camera/flash manuals.

6 Adjust your flash power

Power and distance play a big part in the exposure of your flash. Now you’ve underexposed the background, set the flash to manual and begin by dialling in one-quarter power.
Dial it up or down, or adjust the aperture, to change the subject’s exposure. If the flash is off-camera, moving it closer or further away has as much impact on the result as changing the power or aperture.

FINAL IMAGE

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