Simple rules to improve underwater photography

Here are a few simple rules that will greatly improve underwater pictures.

1. Try to take the picture looking up at your subject
2. Try to ensure the natural sunlight is behind you
3. Fill the picture with your subject
4. Try to have your subject on the diagonal plane rather than horizontal plane
5. Use an external strobe or white balance do not use both or neither.
6. Use a photo editing software to clean up your pics (see this link for more information)

Below are some examples from my photos:

1. Try to Take the picture looking up rather than down on your subject.
The next 2 pictures are not a great example but I think they convey the principle.

Looking down from a 'diver perspective' makes the subject difficult for the camera to see against the background

Looking 'up' at the subject and contrasting the same subject against the water will improve the picture. Not a great example but it conveys the principle.

2. Try to ensure the natural sunlight is behind you it makes a huge difference to the result.

Notice the shadow is in front of the subject: The subject is dark from the camera perspective despite having an external strobe. A lot of the subject detail is lost.

Notice the shadow is behind the subject and the detail of the subject is much more vibrant. The scales are clearly discernible.

3. Fill the picture with your subject - get as close as you can and don't have too many distractions from your subject.

Family of clownish in their anemone but it could be better

I wanted to get closer but he was a very shy little fish. The subject is the focus of the picture with detail of the anemone as background.

Both photos taken of the same subject but the second picture captures the detail of the clown fish and his anemone.

4. Try to have your subject on the diagonal plane rather than horizontal plane

Great subject on the horizontal plane

Picture improved by adjusting the camera angle on the same subject to the diagonal plane

5. Use an external strobe or white balance do not use both or neither i.e. you must use one or the other so if you don't have an external strobe then you must use white balance.
White balance compensates for the loss of red color at depth.
Manual white balance will give the best results but you will need to take something white with you to perform the task at different depths and different visibilities.

Using both external strobe and white balance adds a red hue to the strobe light. The colors appear unnatural

Using external strobe too far away negates its effect. The green hue of the picture is common in incorrectly balanced pictures.

Correct white balance and no flash give improved results

6. Use photo editing software to clean up your pics (see this link for more information).

The only thing that cannot be cleaned up is out of focus pictures.
Try to ensure you are stable when taking a picture.
Always allow the camera time to focus before shooting if you have an auto focus function.