Introduction to the Canon Rebel T2i / EOS 550D : Basic Controls Training DVD by Blue Crane Digital

the exposure MoDOT is where you turn your camera on full automatic control and forget it millions of point-and-shoot photographers never change this setting but we're going to first will divide the shooting modes into groups so they make more sense when you set the camera on auto it does four things for you it focuses the lens the camera judges the amount of light and distance to your subject then the camera determines how fast the shutter should open and close and finally it sets the aperture or size of the lens opening you snap the photo you get an average exposure Canon expands upon this theme with the other basic zone settings each is tailored to specific shooting conditions creative Auto is the most versatile it allows you to control the artistic elements that go into making a great photo the camera controls the rest of the settings for example say you want to take a portrait of a