Abbreviations - A

AA(A)
Small battery size. The AA size is mostly used in digital cameras and Walkmans and is available in Alkaline, NiCd and NiMH qualities. AAA is the smaller variety as used in small flashlights among other devices
ADC
Analog-to-digital Converter – (sometimes called DAC) when capturing images on a digicam light is converted to electrical charge. These charges that build up in the CCD are digitized by passing through an ADC so they can be read by a computer.
AE
Auto Exposure - exposure system that automatically sets the correct combination of shutter speed and aperture value according to existing light conditions
AF
Auto Focus - a system that automatically focuses the camera lens. The two types in use are active and passive auto focus
Av
Aperture Priority - exposure is calculated using the value chosen by the photographer. The corresponding shutter speed is then set automatically to achieve a correct exposure. Av allows for depth of field control - large apertures ensure shallow and small apertures make for large DOF.
ASAP
As Soon As Possible – in conventional photography this denoted when you would have liked your pictures to be ready. It usually took a little longer though.
AVI
Movie sequence in Windows' Audio Video Interleave format. Also see our “Top Tutors” / File Formats / Video Formats.