What can cause the "falloff effect" when using electronic flash?

The "falloff effect" in photography refers to the gradual decrease in light intensity as the distance from the light source increases. When using electronic flash, light diffusion over an area significantly contributes to this phenomenon.

As the electronic flash emits light, it does not spread uniformly across a large area. Instead, the light will illuminate subjects directly in front of the flash more intensely while diminishing as the distance from the source increases. Factors such as the design of the flash, the angle of the light, and any diffusing materials used can influence how the light disperses. When the light is diffused, it spreads out over a larger area, resulting in the more pronounced falloff effect, as the intensity of light decreases rapidly beyond the immediate vicinity of the flash.

In contrast, consistent lighting conditions would not create variability that would lead to falloff; high contrast settings generally refer to the difference between light and dark areas but do not directly affect the diffuse nature of flash lighting; and while proper exposure settings ensure that images are well-lit, they do not directly cause the falloff effect. Instead, they simply result in an accurately exposed image despite the natural decrease in light intensity with distance.