Aperture-Priority Mode is usually listed on the exposure dial as “A.” In addition to the settings allowed in the programmed mode, aperture-priority allows you to choose the aperture. The camera will automatically choose the shutter speed that works best with the aperture you’ve chosen.
Aperture-priority mode works well when you want to blur the background, increase the depth of field, or maintain a specific aperture when the light source is inconsistent. In full auto mode, the camera might choose settings that blur the background. By switching to aperture-priority mode, you might be able to increase the depth of field so more of the scene is in focus. The opposite also applies. In full auto mode the camera might choose settings that create a deep depth of field. If you want to focus on a flower while minimizing the surrounding field, you could switch to aperture-priority mode and choose a smaller aperture (larger number.)
A word of caution with both aperture-priority and shutter-priority modes. If you choose a shutter speed or an aperture that your camera thinks is out of whack, your camera will either flash or beep some type of warning. For example, in shutter-priority mode you might choose a shutter speed that’s too slow or too fast for the range of apertures available on the lens. If that happens, your camera will either flash or beep to let you know it can’t find a suitable aperture to match the shutter speed.
If you haven’t already done so, be sure to read our page on Autoexposure Modes.
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