Most underwater videographers buy a couple of lights and mount them to their camera on arms, illuminating the environment, or a dive buddy at close range. Camera-mounted lights are generally acceptable for highlighting the main subjects in a scene, whether they be fish, fellow divers or a beautiful reef. However, if you want to elevate your creative underwater game, you may want to become familiar with “Practical Lighting Techniques.” Practical light sources are defined as lighting sources that appear in a frame and can be perceived as a part of the on-screen world. In other words, they appear “justified.” (Sometimes “justified light” and “practicals” are terms used as cinematic shorthand.) A handheld or helmet light on a diver would be considered practical lighting but so could a a large light source, hidden from view that mimics the sun’s rays cascading into the opening of a wreck. When topside, cinematographers paint a space with light using available lamps, windows, tv screens or street lights to offer practical, justified light.
Often working in a cave or wreck, in a world of limited natural light, I use other divers to carry practical lights that bring depth and dimension to my underwater world. Yet, even on a bright day in shallow water, a practical light in a diver’s hand can bring focus to your subject, and lead the viewer through a remarkable journey.
Types of Lighting
The video lights that are attached to your camera should be a wide diffuse beam that casts soft light on a large field of view. These same lights can be used off camera to light up regions further away. Wide angle lighting can fill extensive areas and also softly highlight the edges of divers and sea life. Held perpendicular to the camera lens, they sharpen edges helping subjects leap away from the background. The underwater world is a complicated and busy scene. When we sharpen layers of the scene or divide it into regions of light, then dimension and depth are enhanced.
There are numerous manufacturers of lights with wide beams. The price variation between lights may be found in size, lumens, burn time and the quality of build. Be sure to investigate the weight and general buoyancy characteristics of this type of lighting. If it will be hand carried by a diver, then it should be close to neutrally buoyant. A light that is negatively buoyant will not only fatigue your underwater model but it may also change their trim or exceed the lift capacity of their BCD.
Some practicals can be set stationary in a scene to enhance the illusion of sunlight accentuating a space. These instruments should be slightly negatively buoyant so they are stable in the current and surge. They can be mounted to small flexible tripods allowing them to be purposely directed. Care must be taken to avoid any environmental damage caused by placing a light in a scene. I have worked on Hollywood productions and television shows where the size of the practical lighting almost dwarfed the divers. These lights, cabled all the way to the surface for power, needed numerous divers to wrangle the light head and cord to protect the reef or cave.
Narrow beam lights also have an important place in practical lighting. A technical diver’s canister light is more likely to be a narrow beam design. So are small handheld backup lights. These practicals act like light sabers, carrying the viewer’s eyes around the scene. Instruct your model to “play” with the light, raking it around the scene, lighting up points of interest along the way. This movement adds power to a scene. If the diver is swimming directly towards the camera, caution them to point their light in a way that does not penetrate the lens for prolonged periods. It is okay and actually beautiful to periodically pass the light beam across the dome of the camera. This creates a momentary flare in the lens that can be effective. If the diver’s eyes follow the light, we get the notion of exploration unfolding in the scene before us.
Use of Lights
Use practical lights in a variety of ways to diversify your underwater video. Models can either swim away from the camera or towards it using a searchlight technique. Divers can separate themselves from the background of a reef, wreck or cave by hiding a wide beamed light and directing it at the wall while you swim parallel with them, turning their body into more of a silhouette. Models can also be backlit by another diver. In this case, the first diver simply swims towards the camera while the diver behind them points their light directly at their partner’s body in the direction of the camera. The diver’s body acts as shield for the brightest center portion of the light and as a result, they are surrounded with a halo of light in the camera’s point of view.
Practical lights add stimulation and purpose to movement through a frame. They can be of very minimal output, and still offer visual diversity that captures the viewer’s interest. Watch this for examples of how to use practical lighting in your video.
