You can adjust the flash output as easily as normal exposure compensation. Flash exposure compensation can be setup to +/- 3 stops in 1/3-stop increments. (If the camera's exposure compensation is set in 1/2-stop increments, flash exposure compensation is set in 1/2-stop increments)

Press the button until the icon and compensation amount start blinking. Set the flash exposure compensation amount Press the button to set the amount To cancel the flash exposure compensation set the amount to +0 Press the button The flash exposure compensation amount will be set

If the flash exposure compensation has been set with the Speedlite and the camera, the Speedlite's flash exposure compensation amount will override the camera's

Using <>

This is for setting various numeric settings. Pressing the <> (plus) button increases the number, while the <> (minus) button decreases the number.