M: This is a full manual transmission. With this shift, the shutter and aperture of the camera are determined manually.

TV: Shutter first. At this time, the shutter can be set manually, and the aperture is automatically assigned by the camera.

AV: it is the preferred aperture. At this time, you can decide the aperture to be used first, and the shutter is automatically assigned by the camera.

A: Fully automatic.

Some machines. What else is there? p？ Shift (program exposure) This is somewhat similar to automatic shift.

Wang: Are you mistaken?