When photographing underwater, there are three shooting techniques you will find particularly useful as they enable you to produce remarkable and appealing pictures without elaborate set-ups.

For small underwater subjects, choose the Macro Mode. Move to within minimum focusing distance of your subject and depress the shutter button halfway. Then using the LCD monitor, move the camera to sharpen your image. Finally, press the shutter button all the way to take the picture. Utilize the flash diffusion plate on the case to ensure even underwater flash lighting.

The first thing to master with wide-angle shots is keeping the water color blue. To keep water looking blue, first set the White Balance*: choose "Daylight" in shallow water, "Cloudy" for greater depths. Then, get below your subject. Aim upward towards the sky to create dramatic silhouettes.
*If your PowerShot has Underwater Scene Mode, select it for the best results when shooting underwater.

You can also use your Canon Waterproof Case on land — in environments where snow, sand, excess humidity or dust could lead to damage. Ideal for skiing and many other activities, a Canon Waterproof or All-weather Case provides an added measure of safety for your PowerShot camera on land.

The O-ring is the water-tight barrier that seals the PowerShot Waterproof Case and prevents water from reaching your camera. It is critical that you properly prepare the O-ring before closing the Waterproof Case and taking your camera into the water.

Remove the O-ring from its groove in the case. To lift the O-ring, you can use your fingers, tool or another blunt object such as a credit card. Lift first in one spot, then gently pull the O-ring completely out of its groove.

Hold one section of the O-ring between the tips of two fingers — be very careful not to stretch or pull it. Slide the tips of two fingers from your other hand along the entire surface to feel for particles or debris that may be stuck to it and remove them, if necessary. Repeat this process over the entire O-ring. A single strand of hair or grain of sand caught between the seal and its contact surfaces may cause a leak.

When you are certain the O-ring is completely clean, apply a small water-tight grease (droplet) to a clean finger and spread it evenly along the full length of the O-ring using the same careful handling you used in Step 2.

After you have applied the grease, carefully re-insert the O-ring back into its groove in the Waterproof Case. Check it again to be sure that no particles or debris are stuck to the O-ring.

It is critical that you perform a submersion test before diving. The night before the dive, submerge the empty case in a tank of water. Check for leaks. On the day of the dive, repeat this test with the camera loaded in the case — but just for a moment. Check for leaks again. Only after both tests have been successfully completed, your PowerShot Waterproof Case is "dive-ready."

Just as you prepared your case to go into the water before the dive, after the dive you must clean it and prepare it for storage. This post-dive maintenance is essential to preserving the watertight seal on your Waterproof Case.

After each day's dive, remove the camera and soak the case in fresh water and operate all the moving parts. To remove the sand and salt that can accumulate around the inner parts move all the buttons and dials repeatedly — except for the lid buckle. Check for salt in the case's active parts.

If sand has penetrated the case, grasp the case with the buttons pointing downward and vigorously swish it with water. It may be easier to rinse away sand with a steady stream of water.