A new buzz-word expression that has developed among underwater photographers is Close-focus Wide-angle or CFWA. What is it and how do you do it?
Terrestrial photographers have been using wide-angle lenses for years and some caught on to the idea that by getting really close to your subject with a very wide-angle lens on your camera gave you the steep perspective that added drama and put the viewer right in with the subject. Doyen of war photographers, Don McCullin was a great exponent of this technique. He used to say that you need to get close to the action, then closer still.
Photographers often talk about the quality of the glass - their lenses. Underwater, the one aspect that tends to ruin the quality of our pictures is the poor quality of the water we are in. It's full of detritus and plankton. 30-metres of horizontal visibility is thought to be gin-clear whereas if that was all you had in air it would be considered a heavy mist at least. It's a great leveller and sometimes buying better quality cameras can be fraught with disappointment. We need better quality water first! So we use wide-angle lenses not often to get a wider shot but to allow us to get close to our subject without cropping out any part of it.
Whereas a fish-eye lens would be a strange choice for a terrestrial shot, underwater it can make complete sense, allowing you to get really close. The dome at the front makes a virtual image by the refraction of the light as it passes from water to the air inside the dome and it's this the camera focuses on. It used to be the province of only very expensive DSLR cameras in tailor-made housings but now you can get an i-Das fish-eye lens for many compact cameras and the route is open for CFWA pictures. Look at how the steep perspective of the close camera-to-subject position translates into much more interesting pictures! Here are some examples.
Firstly I show you the final shot that was first published in many diving magazines throughout the world and later published in Shark Bytes after the background was simplified by computer retouching in Photoshop.
With moving subjects, the trick is to hold your nerve and let the animal come to you. This Great hammerhead shark was searching for its natural prey, Southern stingrays, hiding under the sand in the Bahamas. The water was so shallow I was able to use natural light and shoot a series of pictures in quick succession.
I didn't need to wait for any underwater flashgun to recycle and get ready for the next shot that can take one or two seconds, which is far too long a delay when recording fast moving subjects.
The shark was maybe 6-metres-long from front to the tip of its tail and that length translates into an interesting perspective when the nearest part is only around 10-centimetres from the camera lens' dome.
Naturally, you need to use a fast shutter-speed (I used 1/500 of a second) to freeze the movement, together with a small lens aperture, and I achieved this by increasing the ISO setting to get that. I simply adjusted the camera in advance to be sure the sand was correctly exposed, checking the result on the camera's LCD screen. I then shot a fast sequence of pictures as the animal passed.
If you shoot in RAW mode, you can adjust the files at leisure later on a suitably equipped PC to get the exactly result you want.
The i-Das fisheye lens will screw directly to the front of an Olympus Tough TG4 camera's underwater housing or it will need an adapter ring to fit it to any housing that has a 67mm thread at the front of its port. It works best with the 28mm (equivalent) lens of the Sony RX100 Mk2 in its housing but you may need to zoom in to that equivalent setting with some later cameras such as the Sony RX100 Mk3 and Mk4. Come in to Ocean Leisure Cameras, the store within the store, and discuss your options with the experts. If you want to know more about the techniques of underwater photography, the Ocean Leisure book department has a wealth of resources and if you like the shark pictures you see here you can read about what it took to get such images, including plenty of pictures, in the new book Shark Bytes, also available from Ocean Leisure!