While the entry technique will vary depending on where you are diving, the conditions and the boat you are diving from, the fundamentals stay the same.
On the whole when you dive, it’s usual that you will have the camera passed to you once you are safely in the water. When a negative entry is required and/or when strong current is present this might not be possible. In these conditions the first thing you need to evaluate is whether it’s prudent to take your camera with you at all. If you have a small camera then it’s possible to cradle it by your belly as you backward roll or hold it high (arm stretched full length) above your head if you giant stride. Above your head is far from ideal as this means you have to choose between holding your camera, weight belt or mask. If the camera hits the water and submerges you run the risk of causing a leak from the force of the impact but clearly the most dangerous part of this whole procedure is that you could simply hit your head with your camera while jumping in. So this really shouldn’t even be considered with anything more than a small point and shoot.
So let’s assume that you are safely in the water, take your camera carefully from whomever is passing it to you as this is when mistakes happen. Once you have it, secure it to yourself. The best method is to use a stretchy lanyard and not a wrist lanyard. Having your camera around your wrist will complicate matters when you need your hands for other things, particularly in an emergency.
Now look at it underwater, you are checking to see if there are any streams of bubbles or water entering the housing. If it passes this test then you and your buddy can descend. While descending hold your camera so the lens or the port is facing down. There is usually extra space in the housing here so by holding it this way, if it leaks, then the water will run passed the camera and collect there, doing as little damage as possible. Watch it and check it, clear the bubbles that are stuck to the camera by fanning your hand close to the housing, so you can get some clear visibility through the housing too.
Descending is most likely when you are going to see a leak but don’t stop being vigilant during the dive. Want to know what to do if it leaks? Read here.
If you want to learn more about underwater photography, this course could be for you.