Pros use reflectors to diffuse studio flashes. Lightshpere does this for handheld flashes.
The Lightsphere is a flash diffuser created by photographer Gary Fong. Designed to be used with a flash that is tipped to bounce off the ceiling, the Lightsphere allows softer, diffuse light to fill in shadows that the bounced light would create on its own. Essentially, it turns an accessory flash into a small softbox, providing more flattering light than the flash can on its own.
Instructions
1. Cut the neck of the milk jug off using the utility knife and discard. Set your flash in the ceiling bounce position. Visualize how you will enlarge the opening on the milk jug to fit snugly over the flash, with the jug handle toward the back of the unit.
2. Use the marker to approximate cut lines around the existing opening. Plan to make a pair of straight cuts to each side of the opening, leaving flaps to provide a friction fit to hold the diffuser in place. Test fit the diffuser over your flash.
3. Trim the flaps of excess length. Be sure the diffuser does not block any sensors on the flash itself. Trim away additional plastic if this is the case. Depending on your flash and the design of the original milk bottle, additional customization may be required.
4. Use the diffused flash as you normally would. Most camera and flash systems with TTL metering will adjust for the reduced light. If not, use exposure compensation on your camera to allow additional exposure.
Tags: your flash