Max Shutter speed
Canon A2100 IS can shoot continuously at max speed of
1 fps and has max shutter speed of
1/1600 sec.
Flash
Unfortunately A2100 IS doesn't have an external flash shoe so you are limited with the built-in flash.
Focusing
Canon A2100 IS features a Contrast Detection autofocusing system. The AF system has 9 points to choose from.
Canon A2100 IS also features
Face detection AF where it intelligently detects the faces in the frame and locks the focus automatically.