P–Q
panorama An exceptionally wide photograph. Generally, they are expected to have about the
same field of view as the human eye—about 75° vertically by 160° horizontally—although there are
no hard and fast standards. Some panoramas encompass a 360° horizontal view. Whatever the
view, a panorama is expected to retain details that you would not get by simply cropping and
enlarging a photo with a normal aspect ratio. Panoramas may be produced by specialized cameras,
orsegmented panoramasmay be created by using software to stitchtogether several normal pho-
tographs that by themselves contain only parts of the final vista. See also entrance pupil.parallax A composition error caused by the discrepancy between view fields of an optical
rangefinder and the lens. Also caused by pivoting the camera incorrectly while taking a segmented
panorama.See also entrance pupil, nodal points.photodiode A semiconductor device that converts light into electrical current.
PictBridge An industry open standard that allows photos to be printed directly from digital cam-
eras connected to a printer without an intervening PC.pixel A picture element, the smallest individual element in an image.
pixelation An effect caused when an image is enlarged so much that individual pixels are easily
seen.pixels per inch (PPI) A measurement of the resolution of an image based on the number of pix-
els that make up 1 inch.plug-in A software module that adds new capabilities to imaging programs such as Adobe
Photoshop and Paint Shop Pro. See also filter.preview screen A small LCD screen on the back of a camera used to compose or look at
photographs.prime lens A lens whose focal length is fixed, as opposed to a zoom lens, which has a variable
focal length. Prime lenses are not as versatile as zooms; often they cost less and yet have better
optics because it’s easier to optimize optics for a single focal length. See also zoom lens and
fixed focus.R
RAW format The uninterpolated data collected directly from the image sensor before processing.
red eye An effect that causes eyes to look red in flash exposures; it’s caused by light reflecting off
the capillary-covered retina.red-eye Reduction mode A mechanism that fires a preliminary flash to close the iris of the eye
before firing the main flash to take the picture.(^210210) GLOSSARY