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A-PEN
Annealed polyethylene
naphthalate-a polyester material used as the base on Advanced Photo System film;
thinner, stronger and flatter than the acetate base traditionally used in consumer
photographic roll films.
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ABC
First featured in Contax
(am I wrong?). Also sometimes refer as AEB (Auto Exposure Control). Auto Bracketing
control: Metering feature that automatically produces three or four different exposures
with one press of the shuttle release. Usually one with the recommended exposure
by the camera reading, others at user specified intervals above or below the recommended
setting.
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Aberration.
Failing in the ability of a lens to produce a true image. There are many forms of
aberration and the lens designer can often correct some only by allowing others to
remain. Generally, the more expensive the lens, the less its aberrations (More attention
to optical quality). While no single lens is called a 'perfect lens'. The "ideal" lense would reproduce
a subject in a faithful, clearly defined image on film. Aberrations, which can be
divided into six basic faults, affect the Ideal performance in an optical system.
a) Spherical aberration. Basically, a beam of light passing through a lens
parallel to the optical axis converges to form 3 focused image on the film. Spherical
aberration is the term for an optical fault caused by the spherical form of a lense
that produces different focus points along the axis for central and marginal rays.
b) Curvature of field.
This optical defect causes points on an object plane perpendicular to the lens axis
to focus on a curved surface rather than a plane.
c) Astigmatism. Rays of light from a single point of an object which is not
on the axis of a lense fail to meet in a single focus thus causing the image of a
point to be drawn out into two sharp lines, one radial to the optical axis and another
perpendicular to this line, in two different planes near the curvature of field.
d) Coma. This optical
defect causes the image of an off-axis point of light to appear as a comet-shaped
blur of light. Coma, as well as curvature of field and astigmatism, degenerate the
image forming ability of the lense at the rims of the picture.
e) Distortion. Even if the first four aberrations were totally eliminated,
images could result that still have a distorted appearance. For an example, an rectangle
may appear as a barrel or pin cushion-shaped object.
f) Chromatic aberration. This aberration is caused by light rays of different
wavelengths coming to focus at different distances from the lense. Blue will focus
at the shortest distance and red at the greatest distance. Since the natural rays
of light are a mixture of colors, each aberration will give a different value corresponding
to each color thus producing blurred images.
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Accessory Shoes
- also often called "
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Adjustable Camera
Commonly called the
manual camera. A camera with manually adjustable settings for distance, lens openings,
and shutter speeds. eg Nikon FM series, Carl Zeiss S2, Pentax K1000, Yashica FX-3
super etc.
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Adjustable-Focus
Lens
A lens that has adjustable
distance settings.
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Advanced Photo
System
A new standard in consumer
photography developed by Kodak and four other System Developing Companies - Canon,
Fuji, Minolta and Nikon - based on a new film format and innovative film, camera
and photofinishing technologies. Generally, APS cameras are more compact in size,
weight and enbodied most of the latest and most advance technologies available. There
are options in various sizes of print out and it will even provide a thumbnail prints
(Contact sheet) for you to select or preview prior to actual printing. There have
a different series of lenses and some of the 35mm format AF lenses can even be shared
(With limitation or effective focal length will increased). You can say, it is a
different system camera all together. So much for the brighter side, but there are drawbacks as well and it is not that economical as I originally thought it
supposed to be.
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AE
(Automatic
Exposure)
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AF-I &
AF-S lenses
Nikon's new series
of AF lenses, involves the intergration of coreless motors into their super telephoto
lenses. This gives these lenses quick, ultra quiet autofocus operations. While the
AF-S lenses housing a silent wave motor for even quicker and quiet operations than
the AF-I lenses, which was being in the stage of being replaced by the newer series.
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Agitation
Keeping the developer,
stop bath, or fixer in a gentle, uniform motion while processing film or paper. Agitation
helps to speed and achieve even development and prevent spotting or staining.
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Alphabetical Coding
:
Some early lenses such as
Nikon and Olympus uses some alphabetical coding to illustratre the composition of
their lenses. Fora na exmaple, each ZUIKO Lens is described with an alphabetical
prefix and suffix such as F . ZUlK0 AUTO-S, AUTO-T, etc. The prefix represents the
number of elements in a lens in alphabetical order. For an instance, "A"=1
element, "B"=2 elements, "D"=4 elements, and so forth. "AUTO"
signifies automatic diaphragm. The suffix represents the type of lense: "S":
Standard, "W"=Wide Angle and "T"=Telephoto.
While another example:
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Ambient Light
The available natural
light completely surrounding a subject. Light already existing in an indoor or outdoor
setting that is not caused by any illumination supplied by the photographer i.e.
not by artificial light source.
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Angle Of View
The area of a scene
that a lens covers or sees. Angle of view is determined by the focal length of the
lens. A wide-angle lens (short-focal-length) includes more of the scene-a wider angle
of view-than a normal (normal-focal-length) or telephoto (long-focal-length) lens.
Currently, the widest view available is 220 degree (achieved by Nikon's Nikkor 6mm
F2.8 fisheye lens - 220 degree; while the narrowest is Nikon, 2000mm F11 Reflex Nikkor,
only slightly over 1 degree of view. It can also be explained as the extent of the
view taken in by a lens. For any particular film size, it varies with the focal length
of the lens. Usually expressed on the diagonal of the image area. Basically,
there are three types of angles which can be measured (based on horizontal, vertical
and diagonals of the film frame), the lense must be designed to cover the widest
angle in the diagonal direction. Thus, the angle of view is the angle between imaginary
lines drawn from the opposite ends of the film plane to the second nodal point of
the lense. All objects within this angle will be recorded by the lense on the film.
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Aperture
Lens opening. The hole
or opening formed by the metal leaf diaphragm inside the lens or the opening in a
camera lens through which light passes to expose the film. The size of aperture is
either fixed or adjustable. Aperture size is usually calibrated in f- numbers-the
larger the number, the smaller the lens opening. Aperture affects depth of field,
the smaller the aperture, the greater is the zone of sharpness, the bigger the aperture,
the zone of sharpness is reduced. The hole or opening formed by the metal leaf diaphragm
inside the lens; controls amount of light and depth of field, prevents vignetting
and reduces lens aberrations; the size of the aperture is indicated by its f-number,
i.e., the ratio of the diameter of the opening to the focal length of the lens; a
large aperture is indicated by a small numerical f-number.
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Aperture Priority
An exposure mode on
an automatic or autofocus camera that lets you set the aperture while the camera
sets the shutter speed for proper exposure. If you change the aperture, or the light
level changes, the shutter speed changes automatically. Apart from the sport or action
arena, aperture priority is the most common & effective automatic preference
in photography. It can also explained as automatic exposure system in which the lens
aperture is set by the photographer, and the camera sets the shutter speed. Can be
used in the stop-down mode with any lens that does not interfere with the metering
system.
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Aperture ring
A ring, located on
the outside of the lens usually behind the focusing ring, which is linked mechanically
to the diaphragm to control the size of the aperture; it is engraved with a set of
numbers called f-numbers or f- stops.
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APO
Apochromatic. Having
the ability to bring all colours of the visible spectrum to a common plane of focus,
within close tolerances, usually refer to a lens with such superior colour correction.
Also refer to "ED", "LD", "SD", "UD".
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Artificial light.
Light from a man-made source, usually restricted to studio photo lamp and domestic
lighting. When used to describe film (also known as Type A or Type B) invariably
means these types of lighting.
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ASA
American Standards
Association. Group that determining numerical ratings of speed for US made photosensitive
products. eg films. In 1982, its role and its influence was narrow down by the establishment
of the ISO (International Standards Organisation).
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Aspect Ratio
The ratio of width
to height in photographic prints - 2:3 in 35 mm pictures to produce photographs most
commonly measuring 3.5
x 5 inches
or 4 x 6
inches;
Advanced Photo System cameras deliver three aspect ratios as selected by the user.
ATA
ATA- This means the
camera supports the electrical interface standard, defined by the PC Card Association
(formerly PCMCIA), known as ATA (AT Attachment). This is the mobile computing equivalent
of the IDE standard for desktop computers. Most computers have ATA support built-in.
ATA is supported by most operating systems like Microsoft Windows 3.1, Windows '95,
Windows CE, IBM OS/2, Apple System 7, etc. ATA is supported by most computer manufacturers
including IBM, Compaq, Packard Bell, Dell, Gateway 2000, etc.
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Aspherical lens
A lens whose curved
surface does not conform to the shape of a sphere; lenses are usually ground or molded
with spherical surfaces; because a spherical surface lens has difficulty in correcting
distortion in ultra-wideangle lenses or coma in large-aperture lenses brought about
by spherical aberration, an aspherical lens is used.
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Auto
Exposure Bracketing:
Auto
Exposure Bracketing performs automatic exposure bracketing with varied shutter speed
and/or aperture.
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Autofocus (AF)
System by which the
camera lens (most popular) or the camera body (only available in Contax AX) automatically
focuses the image of a selected part of the picture subject. The autofocus camera
revolution first popularised with the launch of Minolta's Maxxium. Currently, most
current SLRs are autofocus based.
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Automatic Camera
A camera with a built-in
exposure meter that automatically adjusts the lens opening, shutter speed, or both
(program) for proper exposure.
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Automatic iris.
Lens diaphragm which is controlled by a mechanism in the camera body coupled to the
shutter release. The diaphragm closes to any preset value before the shutter opens
and returns to the fully open position when the shutter closes.
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AV
The Aperture value,
usually refer to aperture settings.
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