Max Shutter speed
Sony A6400 can shoot continuously at max speed of
11.0 fps and has max shutter speed of
1/4000 sec.
Flash
A6400 has a built-in flash, and it also has a flash shoe to mount your external flashes too.
One neat feature that we like about A6400's built-in flash has is that the flash head can be tilted upwards manually using your finger, which can be used to bounce the flash light and create a more pleasing lighting on your subject. It is not a very strong flash so the ceiling/wall or the surface you use for bouncing must be relatively close to the camera.
Focusing
Sony A6400 features both Contrast Detection and Phase Detection autofocus (AF) systems which ensures speed and accuracy of focusing in most situations. The AF system has 425 points to choose from. Sony A6400 also features
Face detection AF where it intelligently detects the faces in the frame and locks the focus automatically. In addition to the face detect AF, A6400 has a more sophisticated feature called
Eye Tracking AF which detects and locks focus to the selected eye of the person in the frame accurately and tracks as the subject moves. Eye tracking AF of Sony A6400 is a perfect feature for shooting portraits and is especially useful when fast lenses are used and the depth of field is very narrow.