Through-The-Lens (TTL) A system of providing viewing and exposure calculation
through the actual lens taking the picture.
tungsten light Light from ordinary room lamps and ceiling fixtures, as opposed to flu-
orescent illumination.
underexposure A condition in which too little light reaches the film or sensor, pro-
ducing a thin negative, a dark slide, a muddy-looking print, or a dark digital image.
unsharp masking The process for increasing the contrast between adjacent pixels in
an image, increasing sharpness, especially around edges.
vignetting Dark corners of an image, often produced by using a lens hood that is too
small for the field of view, a lens that does not completely fill the image frame, or gen-
erated artificially using image-editing techniques.
white balance The adjustment of a digital camera to the color temperature of the light
source. Interior illumination is relatively red; outdoor light is relatively blue. Digital
cameras like the Nikon D7000 set correct white balance automatically or let you do it
through menus. Image editors can often do some color correction of images that were
exposed using the wrong white balance setting, especially when working with RAW files
that contain the information originally captured by the camera before white balance
was applied.
zoom head The capability of an external electronic flash to change the area of its cov-
erage to more closely match the focal length setting of a prime or zoom lens.
David Busch’s Nikon D7000 Guide to Digital SLR Photography500