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Splitting the Difference

Photo: Jill Heinerth

Photo: Jill Heinerth

By Jill Heinerth

We’ve all seen them: over-under split images that show a dive boat on the surface and a happy diver or colourful marine creature below the surface. These all-in-one images often grace the front covers of dive magazines and featured resort ads. They are compelling shots that provide an additional context and frame of reference to our underwater world. Though we often see these types of images in print publications they are not as common in video content. They can be challenging to expose and difficult to focus, but with a few tips, you can add this rich material to your underwater production.

To begin, it is easiest to select a time of day when the lighting is rich and saturated. These golden hours early in the morning and late in the afternoon offer vibrant colors. The low position of the sun bends the light rays, providing the most vivid natural palettes. More importantly, they are not too ‘contrasty’ and are therefore easier to expose. You’ll still need enough of an angle on the sun to get some illumination underwater, so pick a time and direction that is as close to a balanced exposure above and below the surface as possible. The exposure value topside will be different from the one underwater. This is one case where an auto exposure feature will fall short. Manually expose for the topside subjects and add artificial illumination to the underwater scene.

If you don’t quite get the optimum exposure, it is possible to make some corrections in post production. Use a filter on the upper half of the image to darken it or add a colorcast that gives an illusion of sunset. The resulting sequence can be an intense golden setting, contrasted by the cool aquamarine world below.

Light refraction can pose some issues for an over-under image. You may find that one half of your image is well focused and the other is fuzzy. To increase depth of field, use a wide dome with a fisheye lens to bring everything into sharp focus. The curvature of the dome will distort images at the interface between the over and under point, so play with the angle of the housing to capture either a sharp horizontal interface, or tilt the housing to create a uniquely curved scene juxtaposition. If you plan to hold a long shot at the surface, you will discover that your housing is suddenly very heavy. You may not be able to hold it half out of the water for very long without sinking below the waves. I’ve used buoyancy wings or styrofoam boards to support a heavy camera for shots that need to be relatively stable.

When you pop your dome out of the water, you’ll find that little rivulets of water will stream down the dome. This can be distracting, especially if the water pools creating a big blob in the wrong part of your scene. Those water droplets will destroy focus where they land. If you have a glass dome on your camera, a product such as RainX can be applied to the dome to help it shed water. This product may not be safe for your acrylic dome, so check your instruction manual first. Sometimes, evenly licking the lens before the shot will also do the trick.

If you have any scratches in your dome port, this may be the time they rear their ugly head. A scratched dome may fill with water beneath the surface and hide the damage, but topside it will refract light and create an unsightly flare.

Create Impact

I’ve used lengthy over-under sequences to illustrate the life above and below a river, but more often, I use the over-under to start or end a sequence. At the beginning of a dive, slip into the water without your camera. Have the divemaster pass it down to you, but keep the lens half out of the water to avoid water spots and rivulets. Shoot your partner entering the water with a giant stride with the camera lens split and then as they hit the water, tilt down to reveal the glorious swish of water and air mixing as they splash down. This shot alone will add power and context to the beginning of any dive sequence and elevate your professional quality a solid notch. As you tilt down or pan down, be aware that you may need to compensate for exposure changes. If your camera is set for auto exposure, it may do that for you, but some cameras are better than others. A good camera will smoothly transition to the new exposure, where other cameras may ratchet or jump through stepped exposures. Test your particular equipment out in advance of shooting important scenes to see how it performs.

Of course, this technique can be just as beautiful at the end of a dive. Coach your partner to surface and let out a big smile to close the end of a great video sequence. Look at the available light to ensure their face is illuminated (rather than backlit) and plan the shot with them prior to your dive.

Small cameras such as GoPros have the added benefit of being able to enter the water with the camera in hand and fully transition from above to below. Turn the lens toward your face and hold the camera in your outstretched arm as you roll or giant stride into the water. It goes without saying that this is one case when you want to use a lanyard, just in case you drop the camera during the entry. Safety always needs to come first, but it is good to know you won’t lose your investment if you need to catch a mask or grab your regulator.

Invest the time to practice and experiment with over-under shots and you’ll be pleased with the ultimate dynamic video dividends.

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