What is a photographic T-block?

On digital cameras, the T file (also marked with Ts file) is the shutter priority file. Adjust the shutter and the aperture will automatically match the camera.

In high-end cameras in the film age, there are two special shutters to realize long exposure. These two kinds of shutters are called B-gate and T-gate, also called B-gate and T-gate.

The shutter time of door B is calculated from the moment when the shutter is pressed until the moment when the shutter is manually released;

The shutter time of gate T is calculated from the moment when the shutter is pressed for the first time (at this time, the hand can release the shutter and the camera continues to expose) until the moment when the shutter is pressed for the second time.