Backlighting

A guest photo tip column by Jeremy A. Ellis

Lighting techniques vary dramatically underwater and include the use of one strobe, multiple strobes, front lighting, side lighting, backlighting, top lighting, and combinations of all of these techniques. Most underwater photographers blend available-light backgrounds with fill-flash foregrounds to capture captivating seascapes providing the viewer with a strong sense of depth, such as the picture at the right.

Backlighting, which involves primarily illuminating a subject from behind, is a technique that not many photographers use under water, but it can be incorporated as one of several techniques to accentuate or emphasize a subject or to provide a rim light. On land, a potential downside of backlighting is flare, which causes image softening and loss of definition. Flare isn't a significant issue under water, as the density of the water dissipates the light rapidly.

Effective Backlighting
While it may seem counterintuitive to shoot into a light source, backlighting your subjects can produce very unique and striking images. To employ this technique under water, place the light source behind your subject. Backlighting works well when shooting subjects that have strong shape or form, such as the manta ray in the bottom left. Shooting semi-transparent subjects with backlighting can also reveal extra details, such as in the sea fan image in the bottom right.

Using Strobes
Most photographers have experimented with using the sun to serve as the backlight, positioning a diver or animal so that it covers two-thirds or more of the sun and creates a silhouette. Recently, more and more photographers are using strobes to accomplish the same effect, but in a more controlled manner. By detaching the strobe from your housing and using a remote trigger, underwater photographers can easily light subjects from the side or behind. Exactly where a strobe should be placed depends on a number of factors, including the degree to which light either passes through or is blocked by the subject, the power of the strobe, the shape of the subject, the look you hope to create, the lens being used, the water conditions (such as surge or current), and the beam angle of the strobe.  

The slave strobe can be triggered from an optical slave or hardwired and handheld behind the subject by you or an assistant. A cable or a slave sensor on a cable allows the strobe to be hidden. A slave sensor detects sudden changes in the intensity of light so that a slave strobe is triggered the instant it detects the burst of light from the hard-wired primary strobe.

In the picture above, the strobe was placed on the other side of a rock ledge to hide it from view, and an optical slave sensor was used to trigger the strobe when the diver swam into the right position.

In the picture at the right, the strobe was placed inside the rocks, and a lengthy optical slave sensor was run along the outside of the cave to trigger the strobe.

Equipment
I use an INON S2000 strobe, which is pictured at the right, due to its small size. The strobe is slightly smaller and cheaper than the D2000, but is almost as powerful. Its size allows me to easily clip it to a D-ring on my BCD, and also to insert it into crevices and rocks, and to easily change its positions. I have found the S2000 very easy to trigger underwater-even in bright conditions-using a standard INON Optical D Slave Cable that is about 12 feet in length. To weight the cable down, I use standard fishing weights near the slave sensor, and can usually find rocks under water to weight down other parts of the cable.

I also carry a Gorillapod (left), and use a zip tie and weights from the boat to weight it down. One of the benefits of the GorillaPod is the quick release, which permits you to remove the strobe from the tripod without unscrewing the connector. Note that it is difficult to use the GorillaPod in a current or in a surge.

Start Shooting
In many instances, you can create a pleasing look by combining backlighting with some balanced front light. In the picture on the right, I have used the sun to silhouette the diver, a strobe to backlight the sea fan (giving the viewer the impression that the diver's torch is providing the backlight), and front lighting to ensure that the diver's face and hands are visible

Don't get discouraged if you have trouble getting good results the first few times you try it. I have used a lot of trial-and-error to find the right strobe placement in the ever-changing water conditions, and have dedicated entire dives to capturing a single shot.

Don't be afraid to try new approaches to lighting. Backlighting can be magical, and will add both drama and visual impact to your portfolio. Using a unique approach to lighting, such as backlighting, will help your images stand out from the crowd and can define your style.

- Jeremy

Jeremy A. Ellis has been an avid SCUBA diver since 1989 and a PADI instructor since 1995. He is an advocate of conserving our ocean environment, and hopes that his underwater pictures will inspire people to protect our oceans. Visit his website for more photographs and information: http://jeremyaellis.com.

For additional information on using backlighting to enhance your underwater photography and more photography tips, visit www.divephotoguide.com. 

CORAL reminds photographers to practice reef-safe photography at all times. Please use strobes and tripods responsibly: make sure not to disturb any wildlife, manipulate the environment, or stir up sediments while setting up your equipment or taking your shots.