First time advice for underwater photographers
1) For most photos (within 3-4ft), you will need the flash on. Make sure your flash is set to “forced flash”, not “auto-flash”. The flash will add color to your shots, otherwise they will look blue.
2) For most photos, you’ll want to be in macro mode. Learn how to turn macro mode on and off. You need to know the range of your macro mode. For most cameras this range will be 1-2 inches to 2 feet (2.5-5cm to 60cm). Any closer and you can’t take a photo. Further away, you must turn macro mode off. Make sure you are zoomed out (see #4)
3) Turn your internal flash on if you are within 2-3ft of a subject. Further than 3ft, turn the internal flash off. Unless the subject is really interesting and fast (shark, manta ray), I highly suggest getting within 3ft of the subject and using the flash. Otherwise, your photo will look blue. Use auto-white balance when you are using your internal flash. Don’t use “cloudy” white balance or underwater mode with your flash/strobe, that will result in photos that are reddish-orange. Use auto, aperture priority, or full manual mode, depending on your comfort level with camera settings.
4) For now, keep your camera zoomed out (the widest setting). The reason why this is so important is because it affects how closely you can focus, especially in macro mode. If you zoom in, you can’t focus as closely to the subject, and that defeats the purpose of macro mode. The better strategy is to get closer to the subject.
5) Try to get within a few inches of the subject. Try to get very low, at eye-level. Focus at the eyes. Try to get a photo of the subject facing you.
6) If you are taking photos with the flash off (subjects more than 3ft away), also known as using ambient light, and you want better color, you must do 1 of two things – either use the underwater mode, or even better, do a manual white balance (custom white balance).
7) If you leave the flash on, and take a photo of a subject more than 2-3ft away, don’t be surprised if your photo has backscatter in it, unless you are shooting in exceptionally clear water. The only way to solve this is to get closer to the subject, and/or purchase an external strobe.
8) Remember – the closer you are, the better your color, contrast and sharpness will be. Try to “fill the frame” with your subject.
9) Your housing should have come with a “flash diffuser”, although it might be built into the housing. This diffuser will be placed in front of your internal flash and will soften the light. Make sure you use it.
10) If you are having problems with the lag time between focusing on a subject and taking a shot, you can try “locking focus” by pressing halfway down on the shutter button, and then fine-tweaking your composition and making sure you keep the camera very still. This works better for non-moving subjects.
11) You can leave your camera on “auto” mode for now, but if your camera has full manual mode (which you can set the shutter speed and aperture/f-stop independently of each other) – that’s the mode you want to be using.
12) Think about getting an external strobe, that’s the best way to improve your photos. To use the strobe, you need to be able to control your camera’s aperture, and control the power of the strobe.
13) Set up your camera, housing, and strobe indoors – and then take some practice shots indoors. Test your settings. Everything will work similarly to how it will work underwater, although indoors focusing will be easier, and your strobe will appear to be more powerful. I’m surprised how many people wait until they get underwater to try out settings.
14) Last, but not least – concentrate on the following two types of underwater shots.
Close-up shots in macro mode, forced flash, auto-white balance, spot-focus, with the subject no more than 5-6 inches away. Aperture priority (AV) mode if available, F8, otherwise program mode.
Scenic coral/reef shots several feet away, macro mode off, flash off, custom white balance, Evaluative (matrix) metering, only in shallow sunny water (25ft or less). Aperture priority (AV) mode if available at F2.8, otherwise program mode.