:: 03. Pre-Dive Preperations

As previously mentioned, a digital camera, unlike you, cannot be placed directly into water. You must place it in a waterproof case before immersing it. The waterproof case is sealed with the rubber O-ring that fits between the case's front and back halves.

Inspecting and maintaining this O-ring is the key to keeping a dry camera and having fun underwater. It is absolutely crucial for you to check the O-ring and service it each and every time you open and close the housing.

Start the O-ring inspection by removing it from its groove in the case. You can lift the O-ring with your fingers, or you can use the special plastic tool or an object such as a credit card to lift the O-ring in one spot. Then pull it from the rest of the groove. After removing it, thoroughly inspect the groove and the opposite side of the case that comes up against the O-ring. Ensure that no sand, grit, hairs or fibers are stuck there. If you find something, use a clean tissue to wipe it away.

If you put the waterproof case away after a dive without washing it, the salt in the ocean water may crystallize and behave like sand to cause leaks. Be sure, therefore, to remove any white powder around the O-ring. Also check for dirt and grit around the underside of the buckle and the rubber strip that seals the air holes.

Next, hold one part of the O-ring between the tips of two fingers„being very careful not to stretch or pull on it„and slide the tips of two fingers from your other hand along the entire O-ring to feel for any dirt that may be stuck there. In some cases your fingers can sense what your eyes miss. If you feel any debris, remove it with your fingers and then wipe your fingers thoroughly with a clean tissue. Repeat the finger inspection along the O-ring until your are sure it is free from any particles or hairs, and then finally look to ensure it is clean and free from debris. When both inspections are complete, put a small amount of the special grease on a clean finger and spread it along the entire O-ring using the same technique as the inspection to move along its length. When the grease has been applied evenly, insert the O-ring back into the groove in the waterproof case. Check it again to ensure that no fibers or particles are stuck to it. Align the O-ring with the groove in the case to insert it, and if it catches on any part of the edge, use the index fingers of both hands to follow the contours of the groove and nudge the O-ring into place from both sides along its entire length.
Once you have closed the case, perform the submersion test described on the right-hand page before diving.

If you are using the case at a beach where sand is stirred up from the bottom, check it carefully after use to ensure that no sand clings to the buttons or O-ring.

Procedure of Pre-Dive Preperations

	When you are lifting the O-ring, do not jam it up forcefully with the tool. Gently slip the tool alongside the O-ring and very gradually and slowly insert it beneath before levering up.
	Since you can tell by touch if foreign matter is on the O-ring, remove the foreign object with your finger and wipe your finger with a clean tissue. You must not wipe the O-ring directly with a tissue. Moreover, you must be extremely careful not to pull too strongly on the O-ring or it will stretch, prevent the case from closing properly and cause a leak.
	Take a small amount of the special grease on your finger and apply it evenly to the O-ring. If too much is applied, the grease itself can cause a leak. Aim to apply a thin layer.
	Misaligning the O-ring with the groove in the waterproof case will cause a leak. Since you can tell whether or not it is aligned from the O-ringÍs dimensions and shape, ensure that it is properly aligned before closing the case.
	Before you dive, you must always perform a submersion test on the case. Place and fill the entire casing with cotton wool or tissue paper. The night before your dive, check the empty case by submerging it in a tank of water. On the day of the dive, test it again with the camera loaded into the case, but only for a moment. If you want, you can take it with a dive without the camera loaded in the casing just to ensure that there is no leak
	Next, submerge it for several seconds and check for leaks. It is important to be vigilant because water will slowly leak into the case if a strand of hair or grain of dirt is caught in the seal.
	When you submerge the loaded case, point the camera lens downward. If there are any small leaks the water will collect around the lens and not immerse the camera body. Continue to hold the case with the lens pointing down when you check for leaks.

Anti Condensation Fluid and Silica Gel Packages

When you are photographing underwater with a digital camera, the image may suddenly become blurry and you may notice condensation on the glass of the waterproof case and the camera lens. Since digital cameras tend to heat up when in use, this phenomenon may occur when the humidity rises in the waterproof case.

To prevent condensation, prepare the case and load the camera in a dry atmosphere, such as an air-conditioned room. In addition, apply the anti condensation fluid supplied with the waterproof case(*) to the inside of its glass to inhibit condensation. You can also insert small silica gel packages, such as the type provided with condiments or dry goods, into the case overnight.

This section has been extracted from Canon Japan on how to prepare your digital investment.

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