A beauty dish is unique in that it creates a Hard Light that has soft edges. It does not have a “hot spot” in the middle of it like most reflectors, and can be used to make portraits very compelling.
Hard and Soft Light
Why Distance Is Important
Beauty dishes have a “Sweet Spot” where they work the best. The reason this modifier exists is to create a Hard Light source with semi-soft edges, and no hot spot in the middle of the Light. Perfect for portraits.
That being said, these are pretty much only good for portraits. You won’t get the benefits of the Light if your beauty dish is too far from your subject, it will just appear to be a small Light source.
For most beauty dishes, you want to place them from 6 inches to 2 ft from your subject’s Face.