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How to Use Canon XTi AV Controls

The AV controls on a Canon Digital Rebel XTi camera place it into aperture priority mode. This mode allows the user to select an aperture, or lens opening size, while the camera chooses an appropriate shutter speed for a proper exposure. The aperture determines how much of the image area is in focus. This is called the depth of field. A larger aperture reduces depth of field, while a smaller aperture increases it.

Things You'll Need

Canon Digital Rebel XTi camera

Instructions

- 1
  Rotate the mode dial on the top right side of the camera so that the Av indicator aligns with the horizontal bar to the left of the dial.
- 2
  Turn the main dial next to the shutter button to select the desired aperture. The main screen will show the aperture options as the main dial rotates. A larger f number for the aperture value (which indicates a smaller lens aperture) will provide a larger depth of field, with more of the image foreground and background in focus. A smaller number will provide a narrower depth of field, which will focus on less of the image while blurring much of the rest.
- 3
  Press the shutter button halfway down and look through the viewfinder. If the 30" shutter speed blinks, the camera does not have a slow enough shutter speed available for a properly exposed image. The image may end up too dark. Use the main dial to select a larger aperture (which will have a smaller f number). If the 4000 shutter speed blinks in the viewfinder, the camera does not have a shutter speed fast enough for a proper exposure. This could result in a washed out image. Use the main dial to select a smaller aperture (with a larger f number).

Photography