When to prioritize shutter speed

if THE subject’s moving, or you want it to look like it is, pick Tv mode and set an apt shutter speed. The camera will set an aperture to get what it decides is an ideal exposure, but it can only choose from the range on the lens. If the speed needs to be matched with an aperture that’s larger or smaller than those available, the shot may come out too dark or bright – adjust the ISO for a better exposure.