I don’t know a single photographer who owns “too few” accessories. The reality is that most of us are accessory junkies, accumulating some useful, but some quite unnecessary, things in the name of improving our photographs. However, one very useful and necessary accessory, particularly for wildlife photography, is an external flash. While many third party flash heads cost less and will work just fine with your camera, owning at least one dedicated flash is important, as it has been designed to communicate perfectly with your camera. Generally speaking, a single flash is rarely sufficient to act as a main light in wildlife photography. But we don’t really want our flash to be a main source anyway; except perhaps when shooting macro. For other wildlife applications, we simply want to use a flash as a fill light to illuminate some of the shadows and provide a catch light in our subject’s eye.
A great time to use fill flash is when the ambient light on the background is brighter than the light on the subject. You might be wondering if you could just adjust the camera’s exposure settings to make the subject brighter. You could. However, that would cause a new problem in that the background would also get brighter and potentially be overexposed. To avoid this, we need fill flash. The images of the nuthatch below illustrate this point. In these photos, the background is much brighter than the subject, which is lost in the shadows. A correct exposure for the background yielded an underexposed subject. Had I adjusted the camera settings to expose for the nuthatch, I would have overexposed the background and the viewer’s eye would have been drawn to the background since we know that our eyes are first drawn to the lighter areas in a photograph. To solve this issue, I simply added some fill flash. The result was a well-lit subject while the background remained correctly exposed. Notice the effect of the flash on both the bird and the bark. The shadows are filled in nicely and the details are brought out by the use of fill flash. Additionally, the catch light in the bird’s eye adds life to the image.
White-breasted Nuthatch. Canon 7D | 500/4.5| No Fill Flash.
White-breasted Nuthatch. Canon 7D | 500/4.5 | Canon 580ex fill flash at -2 FEC
So how does one use fill flash in the field? All you need is a DSLR and a dedicated flash capable of automatic flash metering and output (Flash exposure compensation) control. Enable the flash head’s high-speed sync, which allows camera and flash to work together at higher shutter speeds. Shoot in Av mode (aperture priority), which gives you control over aperture while the camera selects correct shutter speed to maintain ambient exposure. Keep an eye on the shutter speed. As you adjust the aperture, shutter speeds increase or decrease depending on the aperture adjustment you selected. Make sure to maintain a fast enough shutter speed to avoid ghosting or blurred images. Use FEC (flash exposure compensation) to adjust flash up or down as necessary. As fill flash for wildlife I often shoot between -2 or -3 settings. On bright days, I’ll start with -2 FEC. On darker days or when I’m in shade, I’ll start at -2/3 and adjust as necessary. Since I am shooting at -2 or -3 FEC, I use a better beamer which projects flash a little farther. Again, I’m attempting to open up the shadows in the image.
NOTE: Keep in mind that Fill Flash can be overdone. If you add too much flash, your shots can look artificial and overexposed. Aim for subtlety when using a flash and you’ll really improve your shots. The second nuthatch image still has some slight shadowing evident on bird and bark, but the fill flash is just enough to brighten the foreground, giving prominence to the subject in the frame. I hope you have found this information useful.
Until next time, good light and keep shooting. — KEVIN