The Lumiquest ProMax SoftBox III enlarges and diffuses the light from your flash in the direct flash position. SoftBox III has roughly twice the diffusion surface as the original SoftBox.
Its 8 x 9" surface is over 25 times the size of today's most popular flash heads, producing much softer shadows.
No exposure compensation is required when shooting with TTL exposure control, but SoftBox III will interfere with the on flash auto exposure sensor and autofocus assist. Approximate light loss is 1.25 stops.