The Video Length is determined in the Setup Menu. However, as a battery saving method, when the flash is required the camera will automatically revert to a 10 or 20 second video clip depending on model. This feature cannot be overridden.
Tip: If operating your trail camera in Video Mode and most of your activity occurs at night the Picture Delay can be set to the lowest interval. This will keep the videos triggering as quickly as possible while there is activity in the cameras detection area.