Underwater Video: Manual White Balance and Manual Exposure
Video cameras come in two levels: consumer and prosumer. Most consumer level video cameras don't have manual controls and require you to shoot in automatic modes. Prosumer cameras offer manual controls that will improve your color, saturation, and overall exposure. When I shoot underwater I constantly adjust White Balance, Exposure, and Gain. In this article, I have outlined the very basics of each of these controls and how to use them. At the end of the article I've compiled a list of popular prosumer camera models and their manual functions.
White Balance (wb) All light has a specific color, or color temperature. Halogen lights tend to be warm (orange) where HID and sunlight tend to be cooler (blue). Manual video white balance allows you to modify this color temperature for a more accurate and pleasing color tone. Whether using HID lights, halogen lights, or natural light, white balance each and every time you shoot a new scene. You can perform this procedure with or without a color correction filter.
How to set White Balance
- Determine composition, position your lights, and position your white card.
A white card is a white plastic board that you can carry with you in the water. A dive slate will work fine. If you don't have a white card find something white or near to white in the scene. Light sand can work in a pinch. Make sure the card (or white object) is in the same light as your subject and not shadowed by your housing.
- Fill your entire view with the white object and set your white balance.
First, dial your manual white balance setting to the symbol that looks like a box with two arrows. Confirm the white card or object fills the frame and is illuminated by the same light source as your subject and press the white balance button. When you press the white balance button the symbol will flash. This means your camera is capturing the white point so don't move your camera away. Once it has stopped flashing you'll notice a very obvious color shift. You are now white balanced for this composition, but will need to repeat this procedure for the next composition.
|Exposure On a video camera, the exposure control adjusts the iris and controls how much light reaches the camera's imaging sensor (CCD). Consider exposure a brightness & darkness control. I constantly adjust my video's exposure to minimize highlight burnout and to improve color saturation. This control takes a little more practice than white balance, but is well worth the time invested.
How to set Exposure/Iris
-First, go to your camera's menu and turn on zebra striping to 100%.
In this setting, diagonal lines will appear in areas that are overexposed. (Zebra striping can only be seen in the viewfinder)
- Activate your manual Iris/exposure button. You'll see an f-stop number appear in your monitor and viewfinder. Adjust the exposure up and down and watch what happens to the zebra areas. Select a final position that limits the zebras to just the areas that should be white and lacking detail. Reflections, light sources, and extreme highlights should lack detail and show zebras.
Shutter Speed I rarely adjust this control. Exceptions include well-lit, fast action scenes such as a fish snatching up prey. A fast shutter speed can stop this action for sharper slow motion video. A setting slower than 1/60 will blur the image and make your footage look unnatural.
Gain Gain is an artificial low light function that boasts brightness, but sacrifices image quality. If you can't get enough light by opening your exposure and slowing your shutter speed, gain can salvage a scene. However, if used, your image will look very grainy. Unless you're shooting surveillance footage, turn gain off! (0db)
Does your camera / housing offer manual controls? If you want to manually control your image quality, you'll need a camera and housing combination that provides access. The list below shows the prosumer cameras that can be shot manually, who makes housings for them and what controls can be manipulated with each housings.
Manually Controlled Cameras
- Sony FX1 & Z1
- Sony HC1, HC3, & A1U
- Sony VX-2000 & VX-2100
- Sony PD-150 & PD-170
- Sony TRV-900 & TRV-950
- Sony PD-X10
- Canon XL-H1
- Canon XL-2
- Canon XL-1 & XL-1S
- Canon GL2, XM2, & XV2
- Panasonic HVX-200
Camera models and features change regularly. Please drop us a note or give a call if you need help selecting the best camera and housing for your needs and goals.