Photography under water - Shooting tips
The first part is to get a waterproof housing for the camera, but before we go in more detail - when I say "the camera", I mean the small point and shoot camera that is inexpensive. The reason I say this is that under water digital SLR camera often cost more than the camera itself. I"m not exaggerating, it"s amazing what they cost. Therefore, unless you intend to risk losing your money its best to stick with a cheaper camera first. You can buy these underwater cameras for around $ 150. In fact, it would be much more cheaper for you to buy a brand new high end point and shoot (like the excellent Sony Powershot) and an underwater case for it, than it would to buy almost any housing for its current dSLR.I can not explain it, but unfortunately, that"s the way it is. Therefore, the first part of this is to buy your camera, and be resigned to the fact that you"re not taking your DSLR under water, unless you can afford too part with your money.
If you are wanting to shoot underwater then there are a couple of challenges.
First, there are things under the water that can get in your way or possibly harm you. But putting that aside the major problem is the light, and indeed the lack of light. Ideally, when shooting in deeper waters you will need a with a flash or other source of light so that you can capture good color for your photos. If you"re shooting near the surface, then you need to be able to maintain a small ISO speed, but once you start going deep - about 30-40 feet, have a at look at the shutter speed.
The bottom light at this depth is low, and if you start with shutter speeds of 1 / 30, 1 / 15, or below, what we get is a lot of incredible blurry photos, but unfortunately, we do not know that until we are on the computer (or you have made copies), because I say this with me now, around the world everything looks in focus in its small LCD screen. So, if you are buying a point and shoot underwater camera then see if you can get one with low - noise at high ISO which should be pretty low.
Your other problem is color, and a bluriness or mist on the photos. The great news is Adobe Photoshop allows us to tweak the photos later so we can get better pictures but i am not always a fan of this method - its always best to try and take the best photos you can.which works surprisingly well.