I need help. Currently, I was learning how to set the shutter speed but i have no any basis as my guide line, especially for indoor low light party (condition with external flash light, low ceiling - 3m & hight ceiling - wedding hall / ball room, how to bounce the flash gun since very difficulty to get light reflection from high ceiling). What if I not using flash gun, I set it as high ISO 1200, what is my shutter speed basis guild line. I wish could get your precious consultation & advice. Thank you!