NEEWER TT660 Speedlite Flash Light For Canon/Nikon/Olympus/Pentax Digital SLR Cameras GN58 Approximately 3% faster recycling time, compared to previous model TT56. Zoom head full frame: 24mm-15mm, virtually silent operation. Compatible with Canon Digital EOS, Nikon /Pentax / Olympus DSLR cameras. Superior build quality, including a metal foot for added strength. Neewer TT66 camera flash fits various standard hotshoe-mounted DSLR cameras(Canon, Nikon, Pentax, and Olympus, etc). This Neewer camera flash has a guide number of 58 meters (ISO 1 15MM), allowing you to place the flash away from the subject.With the shortest flash duration of 1/2, second, this shoe mount flash helps you to capture high-speed objects in complete darkness. Using the TT66 Flash: 1. Power Management: Power Switch set to ON, and the flash will start charging. After several seconds, the charging indicator turns red and the flash unit is ready for firing.After use, power off the camera flash by setting Power Switch to OFF.2. Power Control: The camera flash has 8 steps of power output control which are indicated by 8 LED indicators. Press "+" to increase the power from 1/128 to 1/1. In contrast, you can press "-"to reduce the power output level.