The Traveling Photographer: A Guide to Great Travel Photography (2014)
13. Fill Flash
Preventing Shadows from Stealing the Show
Fill flash is an antidote for obscured foregrounds, unwanted silhouettes, harsh shadows, and drab colors resulting from overcast skies. It’s best used when the viewer can’t even tell it’s there.
I used fill flash for the topmost image to make sure our Bhutanese guide’s face was adequately illuminated. The difference between the two images is not dramatic, but it is perceptible. | Nikon D700 • 50 mm 1/250 s • f/7.1 • ISO 500
The most likely scenario in which you’ll opt for using fill flash – not only when traveling – is when you need to reduce the contrast of your scene. A portrait with a backlit subject is a classic example. If you expose your image based on the subject’s face, which is obscured in shadow, you run the risk of overexposing the background; if you base your exposure metering on the background, however, your subject’s face will be much too dark. The fill flash helps to give the subject’s face better color, more detail, and a proper exposure by reducing the range of brightness values in the image without significantly affecting the exposure of the background.
The usefulness of fill flash extends beyond just this application, though. It can reduce harsh shadows produced by full sunlight and it can revive the colors of objects in the foreground that would otherwise look dull under an overcast sky. Fill flash can create a desirable small reflection in the eyes of your subject, which makes them appear more vivid. In all of these examples, the flash is used only for supplemental light, not as the main light source. The natural lighting conditions remain unchanged. This is what makes photos shot with the use of fill flash appealing; the subject isn’t lit by a harsh light, but instead is gently illuminated. The use of fill-flash should not be all too apparent in an image but should add inconspicuously to its quality.
Bright daylight made it difficult to take a portrait of this Tibetan woman in front of the Potala Palace in Lhasa. The flash took care of the harsh shadows and produced a small, pleasant reflection in her eyes (top image). Nikon D300 • 54 mm • 1/320 • f/9 • ISO 400
If you plan on using fill flash, you’ll need either a built-in flash unit or an external one. External flashes offer a better range, are much more versatile, and can provide softer light because of a larger flash area. However, the built-in flash is better than nothing, and in many cases it will serve your needs just fine. There are times when an opportunity for a photo will come and go before you can pull out your external flash, mount it to your camera, and set it up. Unfortunately, not all digital SLRs come equipped with a built-in flash.
A dark foreground in front of a bright sky: Scenes like this are a classic example of when fill flash comes in handy. The output of the camera’s internal flash was more than enough to brighten up the faces and vestments of these two monks practicing on a monastery meadow in Bhutan. | Nikon D700 • 70 mm • 1/250 s • f/11 • ISO 800
Regardless of what type of flash you use, its success depends on its restraint, which the photographer has to impose on it. I got the best results using a combination of program mode (P) and iTTL (with Canon: eTTL), especially when I need to work fast or when the lighting conditions change quickly. Set the flash to iTTL/eTTL with a permanent correction of about -0.7 stops for a normal picture. The correction prevents the foreground from being too bright. These settings are usually preprogrammed on my cameras so that all I need to do is pop up the built-in flash to have fill lighting at hand.
Unfortunately, there may be situations when using fill lighting in program mode will put limits on your creativity. When using automatic exposure (P mode) without fill flash, you can use the program shift function to adjust the aperture and shutter speed combinations to your needs. If you’re using flash, however, this function will be limited. In P mode, your camera tries to produce a properly exposed image and avoid potential errors introduced by the photographer. That’s why it will stop down automatically to prevent the fastest possible flash sync speed from being exceeded.
So you might end up with an aperture of f/16, even though you wouldn’t have used such a small aperture opening otherwise. (Some camera models allow you to set the longest possible flash sync speed individually.) In this picture of two Bhutanese monks, the automatic exposure selected an aperture of f/11. I would have preferred to use a larger aperture to isolate the two protagonists a bit from the background, but since I had no way of telling if they were going to stop in a moment, I opted to be safe rather than sorry. I’d rather have a photo with an aperture of f/11 than miss the moment entirely.
If you have more time at your disposal, you can also program the settings yourself using the manual mode (M) to select the shutter speed and aperture, though you may end up with some failed exposures while you’re still striving to figure out the appropriate combinations of shutter speed and aperture. You can also use the aperture priority and shutter priority modes in conjunction with fill flash. Since it’s possible to make serious and frustrating exposure errors by doing this, however, you should definitely familiarize yourself with this process before your trip.
With compact cameras, you can mitigate the flash’s output with flash exposure compensation. In my experience a correction of about –0.7 stop is still a good starting point. This is really just a reference point, though. Depending on the intensity of light and the distance between the subject and the camera, you may need to increase the flash output. I’ve occasionally bumped up the output of a DSLR built-in flash by a full three stops for the purpose of creating fill lighting when standing at a distance of several meters from my subject in blazing sunlight.
Be careful when using a built-in flash in combination with a large (wide-angle) lens or a lens hood. Because built-in flashes are positioned so close to the optical axis, you can end up with unattractive shadows in your images. In these cases you can try removing the lens hood or increasing the focal length a touch. Even increasing the focal length just a few millimeters is often enough to eliminate the shadows when shooting in the wide-angle range. When that doesn’t solve your problem and you don’t have an external flash unit on hand, your only remaining option is to ameliorate or remove the treacherous half-circle when editing the photo later.
Top: Using a built-in flash with a large lens can produce distracting shadows. Nikon D700 • 24 mm • 1/250 s • f/10 • ISO 800
Top right: I used fill flash to photograph this woman selling jam on Moorea, French Polynesia. The extra light helped brighten up some of the darker areas. | Nikon D700 • 38 mm • 1/60 s • f/4 • ISO 400
Bottom right: Fill flash isn’t limited to SLRs. I photographed these men on Isla del Sol (Bolivia) with a compact camera. They were waiting for a parade to begin. | Nikon P7100 • 55 mm • 1/100 s • f/3.5 • ISO 140