Photographing Birds On or Near Water
I spend a lot of time walking on the shoreline with my camera. Generally the birds keep their distance from intruders, but once in a while they fly or swim close enough to challenge my photography skills.
Choppy waters, glare, uneven lighting, and erratically moving birds all present different challenges for photographers. The merganser duck in the photo below kept bobbing and ducking under the water and then coming up quite a distance away from where he originally ducked under. The pelican flying low close to the surface of the water would continually circle and then dive in head first.
Whenever I am presented with unpredictable bird activity near or in choppy waters, I set the camera to Automatic Exposure Bracketing. The camera take several shots of the same scene instead of just one, thus increasing my chances of getting the right exposure.
Automatic Exposure Bracketing
Most DSLR cameras offer the option of AEB, Automatic Exposure Bracketing. At the very basic level, engaging AEB sets your camera to take 3 shots instead of 1 of the same scene, using different exposure values – in 1/3 or 1/2 stop increments.
DSLR cameras have highly sophisticated light meters, but around water, when conditions are not average, they can give you the wrong exposure. The goal of setting your camera’s AEB is to increase your chances of nailing the exposure, especially in uneven lighting conditions or high contrast situations.
The easiest and most basic way to set AEB is to have the light meter choose a starting exposure, and then bracket that starting exposure. (NOTE: The camera must be set for continuous shooting.) Once set, the camera will automatically take 2 extra shots, and include 1 shot underexposed and 1 shot overexposed.
Multiple Options Available When Using Automatic Exposure Bracketing
AEB is not just about setting the camera to take one shot over-exposing and one shot under-exposing from a pre-set starting point. You have more flexibility than that. If the lighting is such that you need only negative compensation (or positive compensation) you can set the camera’s bracketing settings to take 3 shots in the direction of the desired exposure values. For instance, if you think the light meter is incorrectly gauging the scene to be brighter than it is, set the AEB to take 3 shots in negative exposure range. Conversely, if you think that the light meter is incorrectly gauging the scene to be darker than it is, set the AEB to take 3 shots in the positive exposure range.
Many professional DSLR cameras allow the photographer to specify 2, 3, 5 or 7 exposures (instead of just 3) within the AEB set. Choosing the number of shots is usually on the menu where you choose the 1/2 or 1/3 exposure increment. Check your camera’s manual to learn how to get to this menu.
Getting the Best Exposure Value Before Post Processing
It is true that post processing software enables the photographer to fix most exposure adjustment problems. So why bother with AEB? I use AEB because wild birds move unpredictably and fast. When shooting in uneven or problematic light, a primary concern is to preserve as many tonal values as possible on your image. Engaging the AEB function reduces the chances that your exposures will overshoot the right edge of the histogram, thereby losing critical detail data forever. (For more information on why using the camera’s histogram is important, see Photographing Sandpipers on the Beach).
How Does the Camera Calculate AEB?
AEB sound complicated? It’s not. One of the best web resources I’ve read on the functionality and use of AEB for Canon Cameras is available at this link: Guide to Auto Exposure Bracketing on Canon DSLR. The author is Jason Franke. I especially like the charts the author includes that precisely explain how the camera alters shutter speed or aperture to achieve AEB. Definitely worth a look.