What can cause backscatter in underwater photography?

Backscatter in underwater photography primarily occurs when light from a camera’s flash illuminates suspended particles in the water, such as plankton, silt, or sediment. When the flashlight is directed straight at these particles, it causes them to reflect light back toward the camera and results in unwanted white spots or haze in the image. This phenomenon is particularly pronounced in environments where visibility is limited due to the presence of numerous small particles.

In contrast, while a slow shutter speed can affect motion blur and natural light usage may impact exposure levels, these factors do not directly cause backscatter. Similarly, using natural light only can minimize backscatter since it does not involve a flash that can reflect off particles in the water. However, the direct light from the flashlight toward the particles is what specifically creates the backscatter effect, making the choice focused on the angle and positioning of the flash the most relevant to understanding this photography challenge.