Max Shutter speed
Fujifilm X-S10 can shoot continuously at max speed of
20.0 fps and has max shutter speed of
1/4000 sec. X-S10 also has an electronic shutter which can shoot silently at max speed of
1/32000s. One thing to keep in mind is that electronic shutter may cause rolling shutter / jello effects, and also banding issues under artificial light on your images.
Flash
X-S10 has a built-in flash, and it also has a flash shoe to mount your external flashes too.
Focusing
Fujifilm X-S10 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. Fujifilm X-S10 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, X-S10 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 Fujifilm X-S10 is a perfect feature for shooting portraits and is especially useful when fast lenses are used and the depth of field is very narrow.