RIVIERA UNDERWATER PHOTOs

UNDERWATER DIGITAL PHOTOGRAPHY

Underwater photography is much different than the land photography. Among major physical and mechanical aspects that affect underwater pholography are: light and color loss, water clarity, currents, camera moving factor and housing condensation. Some larger Dive organizations offer complete classes dedicated to the Digital Underwater photography. Digital caméras are complex and need to be understood and set up properly to really get the best results.

LIGHT LOSS

There is much less light underwater that at the surface. Some light is lost irnmediately by reflection from the surface of the water. This effect is more pronounced when the sun is low in the sky. Underwater, light is futther affected by absorption and scattering. Water absorbe light and turns it into heat. Greater depth rneans more absorption and less available light. Particles in the water cause light to scatter further reducing availability.

COLOR LOSS

Color Loss is related to absorption. When water turns light into heat it absorbs the colors with lower energy first. It means that Reds. Oranges and Yellows are absorbed before Greens and Blues. This why many underwater photos appear greenish blue. It is important to remember that color loss is affected by total water distance light passes through. This means both depth from the surface and the distance between caméra and subject. The greater the Total distance, the greater Color Loss.

BLUE OR GREEN PHOTOS

There are several ways to improve color underwater. The simplest » is a red filter. The red filter helps add thé red spectrum back into photos. Don't use the red filter in shallow water or with a flash-this will cause excessive reds in pictures. An extemal strobe is another solution. A strobe will add light to provide clear illumination of subject and proper coloration. Setting White Balance to fluorescent helps Fluorescent is blue light sirnilar to underwater and thé caméra will adjust for this. Setting White Balance to low light can also improve results. Do not use a red filter and strobe at the sarme time or a red filter in less than 20 feet of water.

BLURRY PICTURES

The rnost common cause of blurry photos is not holding the caméra steady. As simple as this sounds, it is much harder to do underwater than on the land. Camera and body buoyancy. currents and wave action all together affect caméra stability. Make sure to push the shutter button with a steady pressure on it. A hard push of the button will cause camera to jerk in your hand-the single most common cause of blurry pictures. If the entire image is blurry, this usually means the camera was not held steady enough. Another major cause is incorrect camera settings. With low light underwater. the camera rmay automatically change the shutter speed (slower) and aperture (larger). This makes the camera extrernely susceptible to "shake". A good mode setting for underwater photography is Sports. In this mode, camera will adjust for faster shutter and srnaller aperture size helping enable better results. If you use Auto or Program mode, be sure to set the White Balance to low light or to fluorescent. If the subject is blurry still but the rest of the picture is sharp, the reason is the wrong camera settings and not a shaking. It is recommended to use Sports mode for moving objects in the underwater photography.

SPOTS IN THE PICTURE

This is called backscattering and is usually caused by particles in the water reflecting back from the flash. This will happen with any camera that has a flash close to the lens. The flash goes out in a straight beam and particles in the water reflect the light back into the lens causing such spots. The best solution is an external strobe. With a strobe, the light reflects back to the strobe and away from the lens. It is not recommended to use the built-in flash underwater. Another helpful item is a flash diffuser. The diffuser will help however will not elirninate backscattering.

SHADOW IN THE CORNER OF PHOTO

It's again caused by the built-in flash. The housing, body and lens partly block the flash and cause some shadow. A flash diffuser will help spread the light from the flash around the lens barrel. A better option is with an external strobe. The external strobe is always recommended for underwater purpose when more light is required. On the other hand, the use of the built-in flash is not generally recommended underwater.

SLOW CAPTURE TiME

There are 3 main stages which affect the speed of image capture. First the camera must focus and set-up, then it takes the image, and finally writes the image to the memory. Many digital cameras use Auto Focus. They must focus prior to capture the image. Depressing the shutter half way will allow camera to prefocus so it is ready to capture image instantly. Mode selection will affect actual capture speed i.e. Sports Mode, will automatically select faster shutter speeds than Auto, Program, Portrait or Low light modes will definitely slow the shutter down.

CONDENSATION

Digital Cameras create small amounts of heat. This cause the air inside the housing to warm slightly. Then a condensation may form by interaction with cold water from the outside of the housing. This is very similar to the fogging inside a cars windshield on a cold night. To minimize condensation

a) avoid to open housing right before diving, especially in humid areas

b) place silica beads in housing to absorb moisture

c) use mask defog on lens area of housing

Keep the housing out of the sun and try to do set up in an air-conditioned or cool room to avoid humid air get in.

SHOOTING TIPS

Try not to shoot strait down direction. It is always better to shoot upwards in order to take advantage of surface light. Shoot many extra images then make your choise while editing on a computer. Approach to the subject as close as possible and preferably with a wide angle. Experiment with différent settings so you can achieve results you like the best.

HANDLE & CARE HINTS

Rinse the housing thoroughly in fresh water after every diving and dry before opening it. Check the Orings before every diving and insure they are clean and free of dust. Keep Orings lightly lubricated with silicone grease. Remove batteries form camera for storage. Keep the housing back opened to avoid flattening Orinqs. Store in a cool and dry place.

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