The
ShiaNet Technology Development Department Presents:
Beyond
Bricks and Mortar: Introduction to Digital Photography
Glossary of Digital Photography Terms
Ambient light – The
natural light in a scene.
Archival – The
ability of a material, including some printing papers and compact discs, to
last for many years.
Aperture
– A small, circular opening inside the lens that can change in diameter to
control the amount of light reaching the camera's sensor as a picture is
taken. The aperture diameter is expressed in f-stops; the lower the number,
the larger the aperture. For instance, the aperture opening when set to f/2.8
is larger than at f/8. The aperture and shutter speed together control the
total amount of light reaching the sensor. A larger aperture passes more light
through to the sensor. Many cameras have an aperture priority mode that allows
you to adjust the aperture to your own liking. See also shutter
speed.
Application – A
computer program, such as an image editor or image browser.
Buffer – Memory in
the camera that stores digital photos before they are written to the memory
card.
Burning – Selectively
darkening part of a photo with an image editing program.
CCD – Charge Coupled
Device: one of the two main types of image sensors used in digital cameras.
When a picture is taken, the CCD is struck by light coming through the
camera’s lens. Each of the thousands or millions of tiny pixels that make up
the CCD convert this light into electrons. The number of electrons, usually
described as the pixel’s accumulated charge, is measured, then converted to a
digital value. This last step occurs outside the CCD, in a camera component
called an analog-to-digital converter.
CD-R – CD-Recordable:
a compact disc that holds either 650 or 700 MB of digital information,
including digital photos. Creating one is commonly referred to as burning a
CD. A CD-R disc can only be written to once, and is an ideal storage
medium for original digital photos.
CD-RW –
CD-Rewritable: similar in virtually all respects to a CD-R, except that a CD-RW
disc can be written and erased many times. This makes them best suited to many
backup tasks, but not for long term storage of original digital photos.
CMOS – Complementary
Metal-Oxide Semiconductor: one of the two main types of image sensors used in
digital cameras. Its basic function is the same as that of a CCD. CMOS sensors
are currently found in only a handful of digital cameras.
CMYK – Cyan, Magenta,
Yellow, Black. The four colors in the inksets of many photo-quality printers.
Some printers use six ink colors to achieve smoother, more photographic
prints. The two additional colors are often lighter shades of cyan and
magenta.
CompactFlash™ – A
common type of digital camera memory card, about the size of a matchbook.
There are two types of cards, Type I and Type II. They vary only in their
thickness, with Type I being slightly thinner. A CompactFlash memory card can
contain either flash memory or a miniature hard drive. The flash memory type
is more prevalent.
Contrast – The
difference between the darkest and lightest areas in a photo. The greater the
difference, the higher the contrast.
Digital camera – A
camera that captures the photo not on film, but in an electronic imaging
sensor that takes the place of film.
Dodging – Selectively
lightening part of a photo with an image editing program.
Download, downloading
– The process of moving computer data from one location to another. Though the
term is normally used to describe the transfer, or downloading, of data from
the Internet, it is also used to describe the transfer of photos from a camera
memory card to the computer. Example: I downloaded photos to my PC.
DPI – Dots per inch:
A measurement of the resolution of a digital photo or digital device,
including digital cameras and printers. The higher the number, the greater the
resolution.
EXIF – Exchangeable
Image File: the file format used by most digital cameras. For example, when a
typical camera is set to record a JPEG, it’s actually recording an EXIF file
that uses JPEG compression to compress the photo data within the file.
External flash – A
supplementary flash unit that connects to the camera with a cable, or is
triggered by the light from the camera’s internal flash. Many fun and creative
effects can be created with external flash.
File – A computer
document.
Fill flash – A flash
technique used to brighten deep shadow areas, typically outdoors on sunny
days. Some digital cameras include a fill flash mode that forces the flash to
fire, even in bright light.
Fire – Slang for
shooting a picture. Example: I pressed the shutter button to fire.
FireWire – A type of
cabling technology for transferring data to and from digital devices at high
speed. Some professional digital cameras and memory card readers connect to
the computer over FireWire. FireWire card readers are typically faster than
those that connect via USB. Also known as IEEE 1394, FireWire was invented by
Apple Computer but is now commonly used with Windows-based PCs as well.
Grayscale – A photo
made up of varying tones of black and white. Grayscale is synonymous with
black and white.
Highlights – The
brightest parts of a photo.
Histogram – A graphic
representation of the range of tones from dark to light in a photo. Some
digital cameras include a histogram feature that enables a precise check on
the exposure of the photo.
Image browser – An
application that enables you to view digital photos. Some browsers also allow
you to rename files, convert photos from one file format to another, add text
descriptions, and more.
Image editor – A
computer program that enables you to adjust a photo to improve its appearance.
With image editing software, you can darken or lighten a photo, rotate it,
adjust its contrast, crop out extraneous detail, remove red-eye and more.
Image resolution -
The number of pixels in a digital photo is commonly referred to as its image
resolution.
Inkjet – A printer
that places ink on the paper by spraying droplets through tiny nozzles.
ISO
speed – A rating of a film’s sensitivity to light. Though digital cameras
don’t use film, they have adopted the same rating system for describing the
sensitivity of the camera’s imaging sensor. Digital cameras often include a
control for adjusting the ISO speed; some will adjust it automatically
depending on the lighting conditions, adjusting it upwards as the available
light dims. Generally, as ISO speed climbs, image quality drops.
JPEG – A standard for
compressing image data developed by the Joint Photographic Experts Group,
hence the name JPEG. Strictly speaking, JPEG is not a file format, it’s a
compression method that is used within a file format, such as the EXIF-JPEG
format common to digital cameras. It is referred to as a lossy format, which
means some quality is lost in achieving JPEG’s high compression rates.
Usually, if a high-quality, low-compression JPEG setting is chosen on a
digital camera, the loss of quality is not detectable to the eye.
LCD – Liquid Crystal
Display: a low-power monitor often used on the top and/or rear of a digital
camera to display settings or the photo itself.
Media – Material that
information is written to and stored on. Digital photography storage media
includes CompactFlash cards and CDs.
Megabyte (MB) – A
measurement of data storage equal to 1024 kilobytes (KB).
Megapixel – Equal to
one million pixels.
Memory Stick®—A
memory card slightly smaller than a single stick of chewing gum. Like
CompactFlash and SmartMedia, it is flash-based storage for your photos.
NiMH – Nickel
Metal-Hydride: a type of rechargeable battery that can be recharged many
times. NiMH batteries provide sufficient power to run digital cameras and
flashes.
Online photo printer
– A company that receives digital photos uploaded to its Web site, prints
them, then sends the prints back by mail or courier.
Panning – A
photography technique in which the camera follows a moving subject. Done
correctly, the subject is sharp and clear, while the background is blurred,
giving a sense of motion to the photo.
Pixel – Picture
Element: digital photographs are comprised of thousands or millions of them;
they are the building blocks of a digital photo.
RAW – The RAW image
format is the data as it comes directly off the CCD, with no in-camera
processing is performed.
Red-eye – The red
glow from a subject’s eyes caused by light from a flash reflecting off the
blood vessels behind the retina in the eye. The effect is most common when
light levels are low, outdoor at night, or indoor in a dimly-lit room.
RGB – Red, Green,
Blue: the three colors to which the human visual system, digital cameras and
many other devices are sensitive.
Saturation – How rich
the colors are in a photo.
Sensitivity – See
ISO speed.
Serial – A method for
connecting an external device such as a printer, scanner, or camera, to a
computer. It has been all but replaced by USB and FireWire in modern
computers.
Sharpness – The
clarity of detail in a photo.
Shutter
speed – The camera’s shutter speed is a measurement of how long its
shutter remains open as the picture is taken. The slower the shutter speed,
the longer the exposure time. When the shutter speed is set to 1/125 or simply
125, this means that the shutter will be open for exactly 1/125th of one
second. The shutter speed and aperture together control the total amount of
light reaching the sensor. Some digital cameras have a shutter priority mode
that allows you to set the shutter speed to your liking. See also
aperture.
SmartMedia™—a
wafer-thin, matchbook size memory card. This is also a flash-memory based
storage medium.
Thumbnail – A small
version of a photo. Image browsers commonly display thumbnails of photos
several or even dozens at a time. In Windows XP’s My Pictures, you can view
thumbnails of photos in both the Thumbnails and Filmstrip view modes.
USB – Universal
Serial Bus: a protocol for transferring data to and from digital devices. Many
digital cameras and memory card readers connect to the USB port on a computer.
USB card readers are typically faster than cameras or readers that connect to
the serial port, but slower than those that connect via FireWire.
White balance – A
function on the camera to compensate for different colors of light being
emitted by different light sources.
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