Under low-light or low-contrast conditions , the built-in AF-assist beam will be emitted automatically to make it easier to autofocus. The 430EX II's AF- assist beam is compatible with the AF points of almost all EOS cameras. The AF-assist beam is compatible with 28mm and longer lenses.
Although using the self-timer or Remote Switch can prevent camera shake, using mirror lockup to prevent camera vibrations can also help when you use a super telephoto lens or shoot close ups. When [
