You can easily fit 85cm umbrella into a softbox with the Godox Diffuser for Parabolic Umbrella. Godox makes installation a snap. Just slip the elastic-edged diffuser over the open end of the umbrella, eliminate spill light with a draw string around the flash head, and you’re done. The diffuser reduces light slightly, but that’s a small price to pay for a soft, enhancing quality of light with moderate contrast and a warm, wraparound look.