In auto mode your camera will automatically decide…if you need to use the flash or not.…If it thinks you do it will activate the flash power…it up and calculate how much flash to add to your scene.…On a lot of cameras though if you don't want flash…and you're shooting in auto mode then you're simply out of luck.…On those cameras the only way to not have flash In that situation is to switch…out of auto mode, other cameras offer a…special flash off setting when they're in auto mode.…On most cameras program mode works just like auto…mode, but you have to activate the flash yourself.…

In other words, program mode gives you the option…of whether or not you want to use the flash.…If you do want it You have to activate it on your own.…When you have TTL mode activated on your flash, and your camera is in…Auto or Program mode, the camera and flash make decisions in a very particular way.…If the camera meters and finds that your scene…has a lot of light in it, a bright outdoor…scene for example.…Then the camera will assume that you want fill flash.…