Glossary

This MINIATURE-GLOSSARY give a very short describtion of terms used in coherence with digital photographing and CHDK, detailed informations can be found e.g. in the Wikipedia.

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AEB

Automatic Exposure Bracketing, taking a series of pictures with automatically increasing or decreasing exposure

ARM

Advanced RISC Machine - an architecture for 32-bit microprocessors, dominant in the mobile electronics market

Av

Aperture value - often used as a setting that allows to choose a specific aperture value while the camera selects a shutter speed to match, the camera will ensure proper exposure (Aperture priority).

AWB

Automatic White Balance - a feature of most digital cameras whereby the camera calculates the best-fit white balance to the image

Bayer filter

a color filter array for arranging RGB color filters on a square grid of photosensors in digital cameras

Bracketing

a general technique of taking several shots of the same subject using different or the same camera settings

Bv

Brightness value

CMOS

Complementary Metal-Oxide-Semiconductor, a class of integrated circuits, used in microprocessors, microcontrollers, RAM and other digital logic circuits, also used for a wide variety of analog circuits

CMYK

short for cyan, magenta, yellow, and key (black), a subtractive color model used in color printing & to describe the printing process itself

CRT

Cathode Ray Tube, a vacuum tube containing an electron gun (a source of electrons) and a fluorescent screen, the mean part of a TV or a monitor

Dark frame subtraction

a way to minimize image noise for pictures taken with long exposure times; it works by taking a picture with the shutter closed, then this “dark frame” is subtracted from the picture

DigiC

a proprietary (32 bit) image processor developed by Canon for cameras (Digic I - IV), video cameras (Digic DV, DV II) and webcams; based on ARM architecture.

DNG

a royalty free RAW image file format designed by Adobe Systems →Digital Negative (file format)

DOF

Depth Of Field - the portion of a scene that appears sharp in the image. Although a lens can precisely focus at only one distance, the decrease in sharpness is gradual on either side of the focused distance, so that within the DOF, the unsharpness is imperceptible under normal viewing conditions. The DOF increases with the f-numbers.

DPOF

Digital Print Order Format, a format for digital camera to define which captured images on the storage card are to be printed

DryOS

an Operating system from Canon for digital cameras and other Canon hardware, such as digital video cameras and high-end webcams

DSLR

Digital Single-Lens Reflex Camera, a digital camera with an automatic mirror system. Based on the single-lens reflex (SLR) principle such cameras uses a mirror to show in a viewfinder the image that will be captured. On shooting the mirror swings beside, the shutter opens and the image is projected and captured on the sensor.

EFL

Effective Focal Length, see FL

Eye-Fi

A memory card in SD-format with wireless LAN (Wi-Fi) capabilities, bundled with additional software to upload photos from the camera to photo sharing sites such as Flickr, Facebook, and PhotoBucket.

Ev

Exposure value - denotes all combinations of camera shutter speed and relative aperture that give the same exposure. Also used to indicate an interval on the photographic exposure scale, with 1 EV corresponding to a standard power-of-2 exposure step, commonly referred to as a 'stop'.

EXIF

Exchangeable Image File Format, a specification for the image file format used by digital cameras --> Wikipedia link

F-number

the focal length divided by the 'effective' aperture diameter. It is a dimensionless number that is a quantitative measure of lens speed, an important concept in photography. A typical notation is F/2.8 or F/8.0

FAT

File Allocation Table, a computer file system architecture from Microsoft

FL

Focal Length - a measure of how strongly an optical system converges (focuses) or diverges (diffuses) light. A system with a shorter focal length has greater optical power than one with a long focal length.

HDR (HDRI, DRI)

High Dynamic Range (Imaging), a technique that allows a greater dynamic range of exposures. The Dynamic Range(DR) is the range of luminance values between light(strongest highlight) and dark areas(darkest shadow).

Hyperfocal distance

the distance beyond which all objects can be brought into an "acceptable" focus. There are two commonly used definitions, leading to values that differ only slightly (he distinction between the two meanings is rarely made, since they are interchangeable and have almost identical values):

1)the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp; that is, the focus distance with the maximum depth of field. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.

2)the hyperfocal distance is the distance beyond which all objects are acceptably sharp, for a lens focused at infinity.

IDA

Interactive Disassembler - a commercial disassembler software for code analysis and debugging

IS

Image Stabilizer

ISO

International Organization for Standardization, an scale for measuring color-negative film speed

JPEG (JPG)

Joint Photographic Experts Group, a method of compression for photographic images, media type format

Lua

A script programming language → www.lua.org

ND filter

Neutral Density filter, "grey" filter on cameras

NTSC

National Television System Committee, the analog television system used in the United States, Canada, Japan, Mexico, the Philippines, South Korea, Taiwan

OSD

On Screen Display

PAL

short for Phase Alternating Line, a colour encoding system used in broadcast television systems, e.g. in europe

PictBridge

An industry standard from the Camera & Imaging Products Association (CIPA) for direct printing which allows images to be printed directly from digital cameras to a printer, without having to connect the camera to a computer.

RAW

Unprocessed photo file / format, see also DNG

RGB

short for Red, Green, Blue, an additive color model in which red, green, and blue light are added together in various ways to reproduce a broad array of colors

Sv

Speed value (determined by ISO setting)

Tone mapping

a technique used in image processing and computer graphics to map a set of colours to another; often to approximate the appearance of high dynamic range images in media with a more limited dynamic range.

Tv

Time value (determined by shutter speed)

VxWorks

a real time operating system from Wind River, licensed by Canon for many of their cameras