Most divers quickly find themselves more obsessed with the macro world especially if they are diving their local sites regularly and they tire of the larger more common and obvious subjects. They start to seek out the little critters that are harder to spot and more impressive to showcase to their land-dwelling friends.
There are five main considerations to take awesome macro pictures and when applied together will make a huge difference to your photography.
Subject
This is extremely important. Not every critter you come across will be in a position to allow for an awesome photo.
Go for the shot, NOT the species count. What I mean by this is straight forward - if you try to take a picture of every animal you encounter you you will have a lot of average-to-bad photos. In many cases your subject is not in a position that will allow you isolate it sufficiently.
Pay attention to the background and the area around your subject. Come in at an angle that reduce the noise and background around your subject and make your subject stand out. This leads us on to the composition of the subject.
Composition
Unless your subject is perched on the tip of a piece coral or crawling on the sand, you will likely have a lot of background material to deal with. You will want a high contrast between your subject and the background to make it stand out. A green nudibranch on green coral is not a good example of the contrast you need to make a great picture.
Typing that last sentence made me think of a German chap I met backpacking who once handed me his camera to take a photo of him and his partner. He asked if I could "make a picture" of him. In English we use the word "take" a photo, the direct translation in German is "make."
In the photo below I was tempted to shoot it straight on an zoom in on the tentacles, but I noticed that if I swam around the rock and came at it from another angle I could achieve an awesome contrast by including the blue background to really bring out the colour on the sea anemone.
In macro photography it is beneficial to think in terms of to make rather than to not take a photo. You need to consider how you will isolate your subject from the noisy background. I have often shown a photo of something cool and rare to a non-diver and I have noted their inability to initially spot what I was referring to.
Lightning
Macro photography is often taken by a downwards pointed camera or a camera facing into a rock or crevice. Hence almost always you will need to introduce lightning of some sort as ambient light will be non-existent.
Using your internal flash (with a diffuser) works well when using compact camera. By getting close to your subject you reduce most or all of the backscatter produced by the flash lighting up particles in the water. Illuminating your subject can be effectively achieved by shining a dive torch on it (or getting your buddy to do this for you).
If using strobes, you will want to bring the strobes as close to your housing as possible.
Creative images can be achieved by having your strobes placed above (if you use one strobe) or if using two strobes you could wrap them around the sides of your subject. These techniques will create shadows that can be very interesting.
Background colour
By adjusting your shutter speed you can choose between taking a photo with a blue or black background.
Faster shutter speed equals black background.
Slower shutter speed equals blue (or sometimes a greenish) coloured background.
Many macro subjects are either still or very slow moving so this gives you options to decide which background colour works best for the photo.
I recently had the pleasure of meeting and diving with photographer Kate Jonker on a trip to South Africa. Check out her work here: website and Instagram. She employs this technique fabulously.
Depth of Field
The closer you zoom in on your subjects the less depth of field you achieve. This requires you to close your aperture to get more of the subject in focus (ie: higher F-stop number).
Having a shallow depth of field can either be desirable or not, depending on how you compose your image or what you are trying to achieve. So have this is back of your mind when taking macro photos. In most cases you will want the eyes or head in focus and then decide how much of the rest of the animal needs to be in focus.
When adding on a wet macro lens to your housing you can achieve impressive results with the added magnification. Depth of field becomes a major consideration in this instance.
The pictures below were taken with and without a wet macro lens.
Notice the difference between the depth of field in the image above and below. In the image above the entire eel and some of the foreground is in focus. The second image below was taken using a wet macro lens and only eyes are in focus. The nose and the rest of the image behind the eyes are slightly blurry.
Refer to my article on shutter speed, aperture and ISO if you need more info on this topic.
This is what a wet lens looks like and it can be carried along with you on the dive in your BCD pocket and applied when needed.
To conclude this blog I wanted to mention a bit about autofocus (AF) settings. Most compact cameras will have more than one autofocus options. On my Sony AF-A is an autofocus setting in which the camera will decide which part of your image it thinks should be in focus. If your subject is tiny and clutching to piece of algae that is drifting around in the current you may want to consider using a continuous AF setting. On Sony this is AF-C. What this does is it tells your camera to lock on to a moving subject and while you compose your shot.
The two photo below are of pigmy pipe-horses. They are so hard to spot and especially hard to photograph because they are so small and they blend in so well to their surroundings. The camera invariably focuses on the background and doesn't pick up the swaying foreground subject. Once you finally achieve focus on the animal, you want the camera AF to lock onto your subject. Using AF-C or similar setting on your camera model will help you achieve the desired result.
The silver foreground is my fish pointer placed in front of the pigmy pipe-horse so that I could find it when I looked at my camera LCD screen. This little bugger was thinner than a grain of rice and less than an inch long. I kept losing sight of it when I tried to take a photo.
Hope these tips help you. My suggestion would be to take special note of photographers whose work you admire. Pay attention to how they compose their images and try to understand what it is about their photo's that makes their work stand out from the crowd.
Special thanks for image of the wet macro lens from Tim at www.underwater.com.au