The Doiron Design LS100C lighting system is designed to combine the light output of a Canon 580EX or 580EXII as a "Master" mounted on camera with a second Canon 580EX, 580EXII or 430EXII speed light as a "Slave" mounted on a LS100C and directed into an Interfit STR 125 Octobox to provide fill light. The 430EXII cannot function as a "Master" speed light.
A speed ring for the STR 125 with four fixed and four retractable rod mounting blocks is included to make assembling the STR 125 much easier than with the Interfit SGM400 or SGM700. The included speed ring mounts directly onto the LS100N and not the 580EX, 580EXII or 430EXII.
A fiber optic link is included to ensure IR communication between the "Master" flash on camera and the "Slave" flash mounted on an LS100C. No sync or off camera shoe cords are required. With the "Master" flash set for A:B ratio, the ratio between bounce flash and fill flash can be controlled.
In addition, with the "Slave" flash set to "A" group, same as the "Master", increased light output is available in the High Speed Sync mode. In this mode, both speed lights can be directed to the subject with or without modifiers.