The SB-900 offers three illumination patterns—standard, center-weighted and even—to provide suitable flash illumination for almost every shooting situation. The standard pattern is basic illumination for usual flash shooting environments. The center-weighted pattern provides larger guide numbers at the center of the image than other illumination patterns at the same focal length, making it particularly suitable for portraits. With the even pattern, the light falloff at the edge of the image is less than with the standard illumination pattern, meaning it is ideal for shooting group photographs indoors.
