D
Dark slide
Light-tight film holder for large format cut film.
Darkcloth
Cloth made of a dark material and placed over the Photographers
head and camera back to help the viewing and focusing of images
on the ground glass screen of a Large format camera.
Day
An eight-hour work period. "That shoot will require a full day."
Day Rate
A pre-agreed, flat-rate fee paid for up to one day of photography. Generally based on an 8-hour day.
Daylight film
Film balanced to a colour temperature of 5400K which will give
a natural result with 'daylight' and also 'flash'.
Daylight tank
A light-tight container for film processing. Film is loaded in
the dark after which all other processing steps can be carried
out in normal light.
Dedicated flash
A flashgun designed for use with a specific camera. It links
directly with the internal camera circuitry to help produce perfectly
exposed photos.
Density
The blackness of an area in a negative or print. Sometimes referred
to as contrast.
(see Contrast)
Depth of field
The distance between the nearest and farthest objects that appear
in acceptably sharp focus in a photograph. Depth of field depends
on the lens aperture, the focal length of the lens, and the distance
from the subject.
(see Aperture & Focal length)
Depth of focus
Very narrow zone on the image side of the lens within which slight
variations in the position of the film will make no appreciable
difference to the focusing of the image.
Dev. (Developer)
A Chemical bath which converts exposed silver halides to black
metallic silver, so making the latent image on exposed films
or photographic papers visible.
(see Latent image)
Developing Tank
A light tight container used for processing film.
(see Daylight tank)
Diaphragm
The device, usually found inside the lens, which uses a set
of interleaving blades to control the size of the aperture.
(see Aperture)
Diffuse Lighting
Lighting that is low or moderate in contrast; an overcast day
is a good example.
Diffuser
Any material capable of letting light scatter (diffuse) through
it.
Digicams
Popular term for a Digital camera. A camera that does not use
traditional silver halide film.
(see Silver Halide)
Digital Asset Management System
A database program designed for tracking and organizing digital files, including documents, images, video etc. Usually the program also allows metadata to be added.
(see Metadata)
Digital Negative
Similar to a RAW file but an open format that does not need manufacturer-specific software, although a digital negative still requires processing before it can be used. Capable of delivering more colour and dynamic range than a TIFF or JPEG digital image file. Adobe 'dng' is a Digital Negative.
(see RAW, JPEG & TIFF)
Digital SLR
A digital SLR is simply a SLR camera that takes photos digitally
(electronically) rather than using traditional film; popular
examples are the Nikon D80 and Canon EOS 40D.
(see SLR)
DIN (Deutsche Industrie Normen)
The German industrial standard for rating film speed. This scale
indicates a doubling of speed by an increase of 3 in the rating;
a rather complicated standard, it fell from widespread use during
the early 'Seventies' although the late German manufacturer Agfa carried on using the system for film identification until more
recently.
(see ISO)
Diopter
Close-up lenses (which screw into the front of an existing lens
and act like a reading glass) are often marked in "diopters"
(2.5 diopter close-up lens) The diopter value of a lens is calculated
by taking the reciprocal of the focal length expressed in meters.
Each diopter is the number of times the focal length of the lens
will divide into one meter
Distortion
There are various lens induced 'distortions' that can effect
the photographic image.
(see: Aberration , Barrel distortion & Pincushion effect )
Dodging
'Local' control of density in photographic printing achieved
by shading (using your hands, small pieces of card or various
other dodging tools), therefore, holding back the image-forming
light from a part of the photo to make that area of the print
lighter.
(see Burning- in)
DPI (Dots Per Inch)
A measurement unit describing the resolution of hardware, such as a computer monitor or digital printer. Although strictly incorrect, it is now often used as the resolution unit for a digital image.
D-SLR
D-SLR is a Digital SLR camera.
(see SLR & Digital SLR)
Dupe
A duplicate of an original. Usually the term is used to describe
a duplicate trannie.
(see copy)
DVD (Digital Versatile Disc)
The leading high-capacity, electro-optical data storage media. Initially capable of storing approximately 4.7gb. Recent revisions of the technology can store more. Some types can be erased and recorded again.
(see Gigabyte)
DX
Nikon Digital format lenses. Nikon Digital SLRs have CCDs smaller
than the area of a 35mm film frame therefore DX lenses will cause
vignetting if used on a 35mm film camera.
(see Vignetting)
DX code
An electrical system built into recent 35mm cameras to automatically
adjust the camera for the correct film speed.
(see 35mm)
E
E6
The number given to a Chemical process for developing colour
transparency film. (created by Kodak but adopted universally
by every other manufacturer).
Emulsion
The light-sensitive material (which is suspended in micro-thin
layers of gelatin) that is coated onto different bases to make
photographic film, or paper.
Enlargement
A print larger than the negative or trannie used to produce it
(blow up).
EOS
A popular autofocus 35mm SLR camera system made by Canon. "EOS"
(Electro Optical System) is also the name of the goddess of dawn
in Greek mythology. First introduced to the world in March 1987
with the EOS650 camera.
(see SLR & 35mm)
EF lens
The lens of the Canon EOS autofocus camera system.
(see EOS & Bayonet)
ESP
'Electro Selective Pattern' a Matrix style metering
found in Olympus cameras.
(see Matrix)
E-TTL
E-TTL (Evaluative-Through The Lens) flash metering. A Canon EOS
flash exposure system that uses a brief pre-flash before the
main flash in order to obtain a more correct exposure.
(see Balanced Fill Flash & EOS)
EXIF data
EXIF (Exchange image file format). This is a standard that allows
information stored with the digital photograph (camera setting
and exposure information) to be used to achieve a balanced colour
when the photo is output on a EXIF data-compliant printer. Many
programs can also read and display this information.
Existing Light
Available light, includes all natural lighting from moonlight
to sunshine; and for photographic purposes, existing light is
also the light that is already on the scene. Therefore it takes
in: room lamps, fluorescent lamps, neon signs, candles, daylight
through windows, and artificially illuminated night scenes.
Exposure
The quantity of light allowed to act on a photographic material;
the lens aperture controls intensity or amount of light, and
the shutter speed (or the enlarger timer in printing) controls
the time.
(See Aperture, Shutter speed & Over exposed )
Exposure compensation
To obtain the best results with certain subjects it may be necessary
to alter the exposure from the value suggested by the camera.
An exposure compensation button [+/-] is now found on most modern
auto cameras. Positive compensation may be needed when the main
subject is darker than the background and negative compensation
may be needed for a subject lighter than the background.
Exposure latitude
The amount by which you can over or under expose a light-sensitive
material with standard processing, and still achieve an acceptable
result.
Exposure meter
An instrument for measuring the amount of light (available or
flash) falling on or being reflected by a subject, and converting
this measurement into usable information: shutter speed and f
stop.
(see Existing light , f-stop & Shutter speed )
Extension tubes
Metal tubes added to 35mm or medium format cameras, to extend
the lens film distance, enabling a magnification greater than
x 1(life size).
(see: Close-up lens & Macro)
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