Lessons from the Shot: Exposure - Aperture by George Hsia


By George Hsia, www.georgehsia.com
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One of the basics is tools photography is to understand the exposure equation.  One side of the equation is the characteristics of the Aperture.
Aperture is the opening of the lens iris that allows light into the camera.  Large or wide aperture means more light gets into the camera.  The aperture also controls Depth of Field.
The Aperture is expressed by an f-stop, i.e., f/2, f/2.8, f/5.6, … f/22 and etc. f/2 allows more light into the camera than f/16. f/2 is considered a large aperture.  f/22 is a small aperture.
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Depth of Field – When the subject is in focus, the depth of field is the amount of space before and after the plane of focus.  The aperture controls the Depth of Field.
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Shallow Depth of Field – When the Depth of Field is shallow, only the plane of focus is clear and sharp.  The foreground and background are out of focus or not sharp.  To get a shallow Depth of Field you need a lens that is able to open to a wide aperture.
Large Depth of Field – When the depth of field is large, more than just the subject is in focus.  The foreground and background will only be slightly out of focus and in the right situations not out of focus at all.  To get a large depth of field the aperture must be very small (large f-stop)
Mastering these techniques are creative tools one uses to make great pictures.