Jason,
This was extracted from the web link that you posted:
"Effect of f-number
For a given subject framing, the DOF is controlled by the lens f-number. Increasing the f-number (reducing the aperture diameter) increases the DOF; however, it also reduces the amount of light transmitted, and increases diffraction, placing a practical limit on the extent to which the aperture size may be reduced. Motion pictures make only limited use of this control; to produce a consistent image quality from shot to shot, cinematographers usually choose a single aperture setting for interiors and another for exteriors, and adjust exposure through the use of camera filters or light levels. Aperture settings are adjusted more frequently in still photography, where variations in depth of field are used to produce a variety of special effects."
Here is another link to close up photography, please read halfway down the article re: DOF
http://www.tcinternet.net/users/nmol...hotography.htm
http://www.shutterfreaks.com/Tips/ControllingDOF.html
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