Underwater silhouettes are easy to achieve and can produce stunning images for your portfolio. They can either be the main subject in your image or used as secondary points of interest with a strobe lit foreground. Either way, adding silhouettes into your shooting style will help elevate your wide angle images.
There are two main ingredients for ambient-light silhouettes. You need a strong subject with a distinctive shape and you need enough contrast between the subject and the background. Common underwater subjects that make good silhouettes include sea lions, sharks, divers and wrecks. To achieve enough contrast, keep the sun behind the subject and isolate the subject in open water. Adding additional points of interest, such as sunbeams and framing the subject in a cave or other similar opening, can further enhance the image. I prefer to use manual exposure settings when shooting silhouettes. If your subject is filling a large portion of your frame, most auto settings will try and compensate by automatically opening up the exposure and giving you a washed-out silhouette with an overexposed background. To offset this, you can dial in some negative exposure compensation when using the auto modes.
Part of shooting an interesting silhouette is just recognizing a good subject when its presented to you. With a little practice, I’m sure you will be adding silhouettes to your shooting repertoire.