I've been reading photographers' discussions on various external strobe accessories. I had these tests done some years back for my textbook, "Photojournalism: The Professionals' Approach." From top to bottom, the Indoor/Outdoor comparisons are for: Direct Flash Bouncing the strobe off a ceiling Lumiquest Omnidome Through an umbrella Off an umbrella Through a softbox Outdoors or in a large ballroom or gymnasium, all the accessories work less well at softening shadows. The scattered light rays coming from the accessories have few surfaces to bounce off. Notice, in the outdoor series, that the shadow behind the model is darker in almost each situation. For these tests, the subject remained at the same distance from the background, and the strobe was located nine feet from the subject. Note that there are newer flash accessories on the market for softening light. All are subject to the same laws of physics.