| Diffraction | A phenomenon in which light waves enter the shadow area of an object. With a photographic lens, exposure is often adjusted by varying the size of the lens\' diaphragm (aperture) to adjust the amount of light passing through the lens. Diffraction in a photographic lens occurs at small apertures where the diaphragm edges obstruct the straight-line path of advancing light waves, causing light rays passing near the edge of the diaphragm to bend around the edges as they pass through the diaphragm. |
