Take any random underwater photograph and it has made use of a submersible flash unit also known as ‘strobe’ or just ‘flash’. Understanding strobes or Flash is a very essential part of underwater photography as they are the source of illumination.
- Need for Strobes
Underwater photography is all about dim waters without the lack of strobe. As water is dense, ambient light levels are quite dim. This is where strobes come to rescue by providing high intensity light that illuminates the subject. A complete palette of colors within the angle of coverage is provided by a strobe. - Automatic Flash
Many cameras have a setting of automatic flash which works according to the light conditions. When the automatic flash settings are set on, the flash will not fire in blue water in presence of ambient light. Similarly, when aiming at close subjects or under low lighting conditions, the flash gets activated. - Strobes- Mode of Operation
Strobes are also known as flashguns and can be used according to lighting conditions. One can use a single strobe or even 2, 3 and 4 strobes can be used to light extremely dull subjects. Strobes working on manual power fire for a smaller duration around 1/500th of a second, but still it changes depending on the power settings of the strobe. By changing the power settings, one can change only the strobe output duration. When you use TTL (through the lens) along with strobes, a pre-flash is fired. This flash measures the exposure, which is then analyzed and this gives an estimation of the proper duration of full strobe output. - Types of Lighting
- Front lighting – front lighting is the easiest lighting to shoot; it casts the shadow of the object which falls on the backside of the subject. This emphasizes the color and vibrance of the subject.
- Side lighting – side lighting gives out the details of the subject and emphasizes its texture. By using side lighting high contrast can be achieved.
- Back lighting – back lighting comes from behind which emphasizes shape and form of the subject, producing bright highlights and reducing saturation.
- Top lighting – top lighting is mainly used in macro photography to illuminate the subject.
- Strobe positioning
A single strobe should be kept away from the camera; either above the camera or at 45 degrees aiming at the subject.
When you are using multiple strobes of equal power place them at either sides of the camera at camera level. This will give an excellent shot with wide lens.
When you are using multiple strobes of unequal power, place the main strobe above the camera at 45 degree. The strobe with lower power should be in the opposite direction.