You are going to think this sounds crazy, but the secret to getting good underwater images is not to go underwater first. The biggest mistake new underwater digital photographers make is to buy a new camera, schedule a dive trip, and take the new camera on a dive. This only leads to frustration, mediocre images.
PRACTICE TOPSIDE FIRST
The best way to learn how your new camera works is to shoot with it topside, becoming familiar with all its functions. Then, eventually, take it underwater. This means that you should take your camera out and photograph flowers to help hone your close-up skills. Trying to digitally capture your active pets will help you become a better fish photographer. Practice working with shutter lag by panning, and photographing a dog or child running in the yard. You will become more adept at taking wide-angle photos underwater by composing topside landscape images.
Work with different types of lighting to see their varying effect. Experiment with sunlight, shade, flash, and low light before you ever even think about donning mask, fins, and snorkel. Use an external flash at different angles when shooting close-ups. Include front lighting, side lighting, top lighting, and back lighting. Find out what ISO speeds work the best for the different setups. Learn the camera controls you’ll use regularly and become very familiar with them all. You need to be able to close your eyes and find each specific control.
ADDING THE HOUSING
Now put the camera in the housing and repeat the process. It may look strange to your neighbors that you are taking pictures in your garden using your underwater housing, but what the heck? By this time, you should know where most of the controls are located.
How much O-ring grease is needed depends on which professional photographer you ask. Some will tell you that the camera will flood if you use too much grease, others say to use plenty. The truth is that too much grease isn’t what floods a camera, but rather the particles that the grease attracts. Put on just enough so you can barely feel that it is greased but it slips easily through our fingers. Use a high-powered magnifier to check all surfaces before closing the housing. Once you grease a housing O-ring, be sure to quickly close the housing. Don’t leave it open waiting for something to fall on the O-ring.
When you reach your dive location, it’s recommended that you take the freshly greased, empty housing on a test dive down to over 60 feet if possible. Push and move all the controls, making sure they all operate properly without any leaks. This procedure is generally only performed on new housings, or ones that have had a manufacturer’s maintenance overhaul. Although you might view this recommendation as a bit paranoid, it will save you. There is nothing worse than having a housing flood on the first day of your two-week dive trip!
Check all the exposed O-rings carefully before each dive trip to make sure none need replacing. Then a rule of thumb is to remove all the surface O-rings every three days for full cleaning. The only exception is if the housing was used in very sandy conditions—and especially if it was set down in the sand. Then, remove and check all the surface O-rings before making another dive.
When you have mastered the digital camera on land and your camera’s housing has been tested to eliminate potential floods, you are ready for your first digital dive. One of the best places to start is by setting the camera to the program mode and shooting with the flash off.
Take several available-light images of your dive buddy, the reef, and schools of swimming fish. Point the camera up toward the surface, hold it level, and point it downward to see how the metering works at the three angles. Use the exposure compensation if necessary to balance each image at the different angles.
USING THE FLASH
Turn on the auxiliary flash and try a few exposures with the flash at a 45-degree angle to your subject. Then try moving the flash above the subject or over the camera to see the effect. If you are not happy with the results, here is quick course in Lighting 101.
One of the best ways to see the effect of the strobe is to use a wide-angle lens and attach the strobe to a long flash arm. Place the flash head so that it is just barely visible in the edge of your pictures. Take several images, adjusting your exposure each time to see how the flash lights the scene. Move the flash to different angles to see different lighting effects, remembering to keep the head visible in the frame. When you see a lighting pattern you like, move the flash so that it is barely out of the scene and push the shutter.
SHOULD YOU DELETE IMAGES?
As you start to take your first underwater images, there will be a tendency to delete the bad ones. Don’t waste your precious underwater time deleting—just keep shooting. Be sure to use a large enough memory card to enable you keep both the good and problem images.
By keeping all your images, you can review the EXIF data embedded in the file and see what you did right on those images that look good and what went wrong on the problem ones. This data will also help you determine the best f/stops, shutter speeds, and ISO settings.
Do not completely trust the image you see on the LCD viewer on the back of the camera. Varying water and lighting conditions may factor in the image output. What looked sharp on the viewer underwater may indeed be out of focus because you were too close. Images that looked overexposed on the viewer may not be as bad as you thought when reviewed on a computer screen. Keep all the files, and delete the ones you don’t want later. The only time you need to delete files underwater is when you have filled up a memory card and you run into a great subject.
You should also keep in mind that digital cameras take longer to shoot images. That is just a shortcoming of some digital cameras, but new innovations are forthcoming. Don’t get impatient when the shutter doesn’t fire right away. Instead, practice your digital skills on stationary subjects at first. Many macro subjects do not move very fast, so you will have plenty of time for the camera to lock in on the correct focus and exposure. If the subject is moving, pan the camera with it, squeeze the shutter, and wait for the camera to fire.