How to Adjust and What Does the Aperture Do?


  Aperture adjustment method:

  1. For DSLRs and DCs with manual controls: Set the mode dial to Aperture Priority (A or Av), then adjust the camera’s command dial.

  2. Manual lens: Rotate the aperture ring on the lens barrel directly.

  3. Some fully automatic digital cameras do not allow aperture adjustment; the camera must rely on its own automatic settings based on the scene at hand.

  A lens hood is a circular assembly of blades that serves several functions:

  1. Controlling luminous flux: A larger aperture (F1.4) lets in more light, enabling faster shutter speeds in low-light conditions; conversely, a smaller aperture (F22) allows less light to enter.

  2. Controlling depth of field: The larger the aperture, the shallower the depth of field (resulting in a more pronounced background blur); the smaller the aperture, the greater the sharpness of both foreground and background (small apertures, such as F11–F16, are commonly used for landscape photography).

  3. In flash photography, the aperture also controls the ratio between the flash and ambient light. Ambient light is regulated by the shutter speed, while the flash output is controlled by the aperture.

  Depth of field: the range of sharpness in front of and behind the plane of focus.

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