Quick Tip on Fill Flash

February 17, 2010

Photo Tips, Wildlife

An accessory flash may not come to mind initially as an important tool for wildlife photography, but I never go out on a shoot without one. I recommend that you pack a flash in your gear bag before you next venture into the field.

Outdoors, a flash can be used for what’s called daylight fill-in flash photography. When an animal is backlit, a flash can fill in the strong shadow that obscures the animal’s face if the subject is within the flash’s range.

These two pictures of a saw-whet owl illustrate the value of using daylight fill-in flash. In this situation, I could have used my camera’s spot meter and set the exposure for the owl, but the sky would have been way overexposed. Therefore, daylight fill-in flash was the way to go.

To do this properly, you need an accessory flash with variable flash output control—that is, plus or minus flash exposure compensation. Accessory flashes are much more powerful than a camera’s built-in flash.

One technique is to set your camera on the aperture priority mode, turn you flash and set it to fully automatic, and then let the camera/flash metering system do the work for you. In many cases, you’ll get an OK result – and in some cases even a perfect result.

Me? I use the following method – when I have the time.

First, set your camera to the Manual exposure mode. Turn off your flash. While in the Manual mode, set the exposure for the existing light conditions. Take a shot, and check your camera’s LCD monitor to make sure you have a good overall exposure of the background. You also may want to check the histogram to see if either side is abruptly cut off. That means details aren’t being recorded, and this is something you can’t always see on the LCD.

Next, turn your flash back on and take a picture with the flash set at -1 1/3 (just a recommended starting point). If your picture on the camera’s LCD monitor looks too much like a flash shot, reduce the flash output to -1 2/3. If it’s still too “flashy” continue to reduce the flash strength in one-third increments until you’re pleased with the results.

If the subject is too dark at the starting point of -1 1/3, increase the flash output to, say, -1. If your picture is still too dark, increase the flash exposure until you’re pleased with the results.

This technique works because even in the Manual mode, the flash operates in the TTL (through the lens) Automatic flash metering mode.
You can extend the flash range by attaching a flash extender to your flash (I use the Better Beamer). You also can extend the range by increasing the ISO settings. As you increase the ISO setting, your camera’s image sensor becomes more sensitive to light. So, in effect, the light from the flash travels farther.

Sure, you could always decide to go without a fill-flash and try to open up the shadows in your editing program, but that works only to a degree. The more you open up a shadow, the more digital noise you’ll see in those shadow areas. You also may see a real lack of detail. Remember, the image sensor can only capture a certain range of exposure, from light to dark. Go past that in either direction, and you’ll have problems.

Always strive for the best possible in-camera pictures, which sometimes call for daytime fill-flash. That way, you can spend more time outdoors taking pictures—and having fun with your photography—and less time in your digital darkroom.

Explore the Light,



This post was written by:

- who has written 171 posts on The Digital Photo Experience.

Canon Explorer of Light Rick Sammon has published 36 books, including Exploring the Light and Digital Photography Secrets.

When asked about his photo specialty, Rick says, “My specialty is not specializing.”

You can follow Rick on twitter at http://twitter.com/RickSammon and visit his website at http://www.ricksammon.com

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3 Responses to “Quick Tip on Fill Flash”

  1. Heymo Says:

    Hey Rick,

    nicely done step-by-step instruction. Thanks!


  2. Soren Hedberg Says:

    Hey Rick,

    Does the flash from the camera spook the wild animals?


  3. Bill Page Says:

    Thanks I listen to you often.Very informative.Would like to do your field trips someday.
    Thanks Bill Page Jr


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