What is Camera Flash TTL?

Camera flash TTL was first introduced in the 80's by Nikon. It stands for 'through the lens' and refers to how the flash on the camera works. Many photographers love the TTL technology, while others can live without it. Here, we will break down the technology in layman's terms to understand.

How Flash Works

With TTL flash, once the shutter is triggered the light from the flash fires. The light will travel to the subject being photographed, bounce off it, and re-enter the lens of the camera. From there, the light bounces over to the film sensor. From there, the sensor determines the proper exposure and exposes the shot. This whole process happens in a split second.

Why It's Used

TTL flash corrects the issue of under or over exposure. TTL is commonly used in outdoor settings since light sensitivity can kill an otherwise good shot. With TTL technology, the aperture or shutter speed doesn't matter with the flash, since the correct lighting is being adjusted internally regardless.


TTL takes the guesswork out the f/stop issue. Many photographers enjoy being able to snap photos on a whim without having to worry about making adjustments to the speed or aperture.

Popular Cameras for High Quality Photos: