>>8687091You don't NEED a strobe and diffuser if you know about light.
When I go to conventions, I generally only take my camera, a backup body, my lenses, and a reflector. Shooting outdoors, you don't need more than a speedlight (really, the pop up flash is sufficient).
Plus, if I am just shooting random cosplayers at a convention or whatever, a strobe and diffuser isn't going to make their cosplays look any better.