Digital SLR Camera Basics
A filter fitted in front of the image sensor to reduce moiré by filtering ultraviolet and infrared light.
See also: moiré
The window in which the photographer frames the subject and checks focus. An electronic display such as a monitor can also be used as a viewfinder; in contrast to such electronic viewfinders, optical viewfinders consist of only of optical components such as lenses, prisms, and mirrors.
The exposure that will produce a photograph with optimal brightness.
optional flash unit (Speedlight)
A flash unit that can be mounted on the camera accessory shoe. Optional flash units are generally more powerful than built-in flash units and have features adapted specifically to flash photography. Even if the camera is equipped with a built-in flash, optional flash units can provide lighting and features not supported by the built-in flash.
Exposure greater than the optimal amount. Photographs that are overexposed are brighter than expected.