If the camera has a depth-of-field preview button, pressing it will fire the flash continuously for 1 sec. This is call the modeling flash.

It enables you to see the shadow effect on the subject and the lighting balance. You can fire the modeling flash for wireless and normal flash shooting.

! Do not fire the modeling flash more than 10 consecutive times. If you fire the modeling flash 10 consecutive times, allow the Speedlite to rest for at least 10 min. to avoid overheating and deteriorating the flash head.

The modeling flash cannot be fired with the EOS Rebel 2000/300 and Type-B cameras.