#1. "RE: Diffuser for SB910" In response to Reply # 0
Diffusers are useless for the situations that you mentioned. Diffusers scatter some of the light from the flash so that it will bounce off walls, ceilings or other reflectors to fill in shadows and soften the contrast of direct flash. Outdoors there are generally no reflective surfaces, so the scattered light does not fall on the subject, and is just wasted.