18. Sep, 2016

The magic world of Close Focus Wide Angle.

Two basic principles planted in the head of the beginning underwater photographer are: always use an upward angle of your camera,  and  get  as close as possible  to your subject. These two rules of the thumb are related to the fact that we take pictures in a tricky medium called water. Since the sunlight comes from above, pointing your camera upwards will bring in more light and contrast in your pictures. For example in the Red Sea choosing a horizontal or a more vertical position means  a difference of two f-stops. The vertical  position also  allows to use a  smaller aperture, and thus obtain a greater  depth of field. 

Light under water The major handicap of the UW photographer is that light under water travels over a much shorter distance than on land. Moreover, small particles floating in the water will make light bounce in all directions, producing less contrast and clarity in your pictures. To make it even worse: in water the  warmer colors are  absorbed  progressively when light has to pass a greater mass of water. The amount of color absorption depends on the total distance of  light travelling to your camera: so for a shark at a depth of 3 meters and 2 meters from your camera, light has to travel 5 meters. This holds for sunlight as well as artificial light.  That’s why  getting close is so important: the closer you are, the better your color, contrast and sharpness will be.

Strobes  Strobes can  help  to  restore color and contrast to some extent, but they should be carefully mixed with ambient light to create a natural or more artistic effect. Finding the right balance between the two light sources is the greatest challenge. At least when your purpose is to create an image of the environment as well. Color absorption can be largely restored, but only for subjects at a short distance (< 2 meter)  to the strobe.  You should also be aware of the fact that small changes in distance have large  effects on the lighting of your subject. This is because  light intensity changes with  the  inverse of the squared distance. It will change even more dramatically when you are very close to your subject. For example, if you  are shooting a close up of an anemone fish and  decide to change your distance from 10 to 20 cm, the drop in light will be  3/4 or two f-stops.  Meaning that  you need to  widen the aperture from  f11 to  f5.6,  or set your strobes at a two times smaller intensity.

The magic of  Close Focus Wide Angle That  being said,  I’d like to mention  a technique that has become my favorite on my underwater photography  trips. It’s called CFWA,  a short for  Close Focus Wide Angle.  The 'magic' of CFWA is twofold:  it comes from the  forced perspective  and  the enhanced lighting and color contrast of the foreground subject, a bit like the 'clair obscur' in  Rembrandt's paintings. Although the principle of CFWA is pretty old, the technique has become increasingly popular with more frequent use of fish eye lenses. Alex Mustard, one of its promoters described CFWA in his new book as  ‘the most important technique in underwater photography’*.  CFWA can be seen as an extension of the mixed lighting technique in UW photography. Mixed lighting has always been associated with wide angle shooting. But the fish eye lens has further expanded the magic of its application. The basic principle is to get very close to your ‘target’, preferably a nice colorful object and then combine a flash-lit  foreground  with  a background illuminated by natural light. Only the fish eye equipped with a small dome lens will allow you to focus as close as 10-20 cm. The revolutionary side of CFWA is that it produces dramatic images that are outside the range of normal wide angle lenses. Mostly by combining  two sides of UW photography:  ‘near’ and ‘far’ scenes.  The pictures show an ultra wide coverage of the underwater world with often dramatic perspective effects. A related technique is Wide-Angle Macro (WAM). Here the photographer gets even closer to his subjects. This is achieved with some adaptations  of the position of the strobes like mounting them direct on the housing, and using an even smaller dome port. The more compact your camera rig the better.

*Further reading:

Underwater. Photography Masterclass. Alex Mustard. Ammonite Press 2016.