Coconut OctopusA juvenile Coconut Octopus (Amphioctopus marginatus) uses clam shells for protection - Lembeh Strait, Indonesia.
The 50mm lens is a favourite among many DSLR photographers for topside use because of its wide aperture of f/1.4, which produces images with a very shallow depth-of-field and soft, blurred backgrounds (bokeh). For macro, using a 60mm lens is certainly more versatile and easier to shoot with; however, shooting below f/2.8 is quite unique for underwater photography, and the 50mm’s bokeh is simply stunning.
Here are some tips to help you get started using your 50mm lens underwater with a macro port, with an emphasis on using natural light instead of strobes, which will give your images a more organic feel.
1. Because it’s not a true macro lens, the closest focusing distance of the 50mm lens is quite large, at 45cm, so it’s advisable to fix a diopter on the lens or macro port so you can get closer to your subject (e.g., a +4 close-up diopter). Although fine for subjects of a small/medium size, such as a frogfish, anything smaller than ~4cm should be avoided.
2. Before using underwater, practice using the “custom/manual/preset” white balance mode of your camera on land first. For the best results, shoot in shallow depths (<12m) with bright natural light, setting the white balance manually at different depths, with your strobes turned off. You can white balance either on your hand or a white slate, but I often get good results using light sand, rock or coral. A friend of mine swears by using a white shower cap wrapped over his large dome port to achieve perfect white balance.
3. Shooting at wide apertures of f/1.4 – f/2.8 lets in a great deal of light, so you’ll need to keep your ISO and exposure value (EV) to a minimum, and your shutter speeds may range from 1/320s even up to 1/2000s. This all depends on the light conditions.
4. With a razor-thin depth of field at f/1.4, it’s difficult to get sharp focus on the eye of a moving animal, so start by shooting static subjects. Locking the focus and working manually may help if you have problems with autofocus at such a wide aperture. You don’t have to stick to f/1.4; I find f/2 is easier to work with but still gives dreamy-looking bokeh, so vary the aperture slightly and see what works for you.
5. When shooting macro with natural light, shoot from a low angle with the sunlight behind you, and be careful to avoid casting a shadow on your subject with your body or camera.
6. Although setting the white balance manually, the colour of the RAW image may appear different to what you saw. Often you still need to make slight adjustments of white balance with editing software (e.g., Photoshop, Lightroom) to achieve the best result. Shooting macro with flash, your subjects will be bright and colourful. Shooting with natural light, images have less contrast and colours appear more subtle, which gives a very unique and natural-looking image.
Christian Loader (29, UK) is a professional photographer for Scubazoo Images. He has worked extensively throughout Southeast Asia as an underwater videographer and photographer, and is currently based in Kota Kinabalu, Sabah, Malaysia.