How we test flashguns
For flashguns, we check features, such as flash exposure compensation, motorised zoom heads and advanced flash modes. To test power output, we use a Sekonic flash meter placed 1m from each flashgun. We test the range of manual power settings in one-stop increments – with a sensitivity of ISO 100, the figures correlate with the Gn (Guide number), a common measurement of flash power. The results are checked against shots of a standard grey card and the camera’s histogram display. We also check the accuracy and consistency of TTL flash metering, and the time taken to return to readiness after a full-power flash.