TTL lighting can either be one of the simplest or most difficult lighting modes to work with. It stands for Through the Lens Metering, and photographer Joe McNally is teaming up with Profoto to explain it to you in the video after the jump along with other things like lighting ratios and high speed sync.

TTL works by working with the camera’s metering–specifically with the aperture and the ISO since they directly affect the way the light is rendered in the scene. He also evangelizes the Profoto Air system, which we have to admit is very good. What you may not know is how the pre-flash works in TTL communication.

The other videos explain lighting ratios and how they work. This is more complicated and involves using more than one light source–they’re best done manually to ensure that you get exactly what you want but Profoto and other systems let you set lights up in ratios. Beyond that, they also talk about High Speed Sync, which involves shooting with a faster shutter speed than the camera typically allows to kill more ambient lighting. If you can’t shoot with high speed sync with your flash (not be confused with flash duration), many photographers have used ND filters to get the same effect.