Effect of aperture

The aperture increases or reduces the light beam (thickness) which passes through the lens, controlling how much light strikes the CCD.

• Widening the beam by opening the aperture

Objects closer and farther than the focused subject will be more out of focus. For instance, if you take a picture of a person against a landscape with the aperture open, the landscape in front of and behind the person will be blurred, emphasizing only the person.

• Narrowing the beam by closing the aperture

The range in focus expands forward and back. For instance, if you take a picture of a person against a landscape with the aperture narrowed, the landscape in front of and behind the person will be in focus.

• When you focus on a portion of the subject, there is a range in which object closer and farther will also be in focus. This focused range is called the depth of field.

•As the aperture is stopped down, the depth of field (focused range) increases (wider range of focus).

•Also, the wide-angle lens, and the farther away the subject, the wider the depth of field.

•Zoom lenses do not have a scale for depth of field because of their structure.

•The depth of field for the wdiffers depending on the lens but, compared to when using a 35mm camera, the value is roughly one aperture setting lower (the focused range becomes narrower).

Further, check the depth of field at one stop open side for lenses with a depth of field scale.

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8 Appendix