Why do underwater photographers use a strobe even in clear w

Why do underwater photographers use a \'strobe\', even in clear, well illuminated water?

Solution

Even in the seemingly clear, blue, and idyllic tropical waters, there are always some suspended particles that go unnoticed to the human eye. Whatever it is—plankton, sand, or just little bits of muck floating by—it will have a knack for showing up in your underwater photograph. When this particulate is illuminated by yourstrobes and plays a starring role in your images, it’s called backscatter, and it is the underwater photographer’s arch nemeses.

Backscatter in underwater images is an unfortunate reality of underwater photography, but luckily there are ways you can minimize it and sometimes even eliminate it. The first step in preventing backscatter is to learn why it shows up in your images. Backscatter occurs when the light from your strobe hits a particle in the water and is reflected back into your lens. This lights up all the tiny specks that are unnoticeable until your strobe illuminates them, and makes images look like they were taken in a dust storm. Therefore, when eliminating backscatter from your image, you need to figure out how to minimize the amount of reflected particulates between your subject and your lens.