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Glossary
Photographic Equipment
A Glossary of Miscellaneous Photographic Terms
Almost all camera manufacturers have adapted their particular terminology
and ways of describing many of the entries contained in this glossary. The
terms that follow are defined based on standard Nikon School definitions,
and some terms are particular to Nikon cameras, equipment, and photographic
technology.
Action Viewfinder
An eye-level viewfinder that allows the entire viewfield to be seen five
or six centimeters away from the finder. This finder is useful for
shooting sports or other fast-moving action with a telephoto lens, or
for copy work that requires the photographer to look into the viewfinder
for a long time.
Angle of View
See Picture Angle.
Aperture
The variable opening in a lens which controls the passing of light
through the lens. Usually referred to as an f/stop.
Depth-of-Field Preview Function
Most SLR cameras use full-aperture viewing, and this prevents the
viewing of a picture''s depth of field or zone of sharpest focus.
Advanced cameras include a control that can close the lens to the actual
taking aperture, thus enabling a preview of a picture''s depth of field.
Diaphragm
See Aperture.
Diopter
A measure of lens power equal to the reciprocal of the focal length in
meters. Eyeglass prescriptions are generally indicated in diopters. For
cameras, the diopter is used as the measure of the dioptric power for
the image in the viewfinder.
Dioptric Power
Apparent image distance through optics such as viewfinders. Rated in
diopters. A plus sign is used for positive lenses, a minus sign for
negative lenses.
Eye Level Viewfinder
Allows the photographer to hold the camera at eye level. Most
35mm-format cameras use this finder as the standard type. Usually shows
an unreversed, upright image.
Eyepoint
The farthest point on the optical axis where the entire image inside the
viewfinder can be seen.
Eyepiece Correction Lens
Attaches to the viewfinder eyepiece for eyesight adjustment. Various
models are available to suit far-sighted or near-sighted photographers.
Some cameras have built-in eyesight adjustment.
Eyepiece Magnifier (DG-2)
Accessory which attaches to the camera''s viewfinder eyepiece; magnifies
the image for easier manual focusing. Useful for manual focusing on
subjects with fine detail.
Eyepiece Shutter
A built-in device that prevents light from entering the viewfinder
eyepiece and adversely affecting the automatic exposure meter reading.
Useful for unattended shooting, self-timer operation or cases in which
the photographer has to remove his or her eye from the eyepiece.
Film Advance Mode
Cameras with a built-in motor drive for advancing the film usually offer
two film advance modes: single-frame and continuous framing. With
single-frame, the film is advanced one frame each time the shutter is
released. With continuous, pictures continue to be taken as long as the
shutter release button is fully depressed.
Film Pressure Plate
A part of the camera back which, when closed against the film guide
rails, creates a very precise tunnel in which the film is flatly
positioned for sharpness.
f-Number
The numerical expression of the relative aperture of a lens; equal to
the focal length divided by the effective aperture of the lens opening.
Each f-number is 1.4 times larger than the preceding one, i.e., from 1.4
to 2 to 2.8 to 4, etc. Each number indicates a halving or doubling of
the amount of light allowed to pass through the lens; the next higher
numbered f-number signifies an aperture that lets in exactly one-half as
much light; the next lower number, twice as much. Effective aperture is
the apparent diameter of the diaphragm viewed from the front of the
lens.
Frame Coverage
Except for cameras with 100% viewfinder coverage, most camera
viewfinders show less of the scene than will actually appear on the
film. Finder coverage is expressed as a percentage of the actual scene
that will appear on film.
High Eyepoint
An extended distance from the eyepiece to the eyepoint. Persons who wear
glasses usually cannot see the entire frame image because they must back
away from the viewfinder eyepiece. A high-eyepoint viewfinder enables
the photographer to see the entire frame at a short distance from the
viewfinder eyepiece.
High-Magnification Viewfinder (DW-21, DW4)
A viewfinder that is used for viewing the entire image at a
magnification higher than that with the standard viewfinder. Useful for
close-up work, copy stand work and when trying to focus on subjects with
fine detail.
Image Circle
The circle on the focal plane where a sharp image of the subject is
formed. Indicated by the diameter of the circle. As the image circle
depends on aperture and shooting distance, both aperture and shooting
distance should be specified when the image circle is indicated. With
PC-Nikkor lenses, the amount of "shift" is limited by the image circle.
Large-format cameras with shift/tilt control require an image circle
larger than the film frame.
Infrared Photography
Taking pictures in invisible infrared rays with wavelengths longer than
700nm. In infrared photography, black-and-white film makes
objects/scenes with few infrared rays (e.g., blue sky) appear dark,
while objects/scenes that reflect infrared rays (e.g., green leaves)
come out bright in the picture. To perform infrared photography, IR
filters that transmit long-wavelength rays are necessary. As the plane
of sharpest focus is farther away than in visible light photography, it
is necessary to shift the lens focusing ring to the infrared
compensation index.
Lens Shutter
A shutter located near or inside the lens optical system. With a lens
shutter, the entire frame is exposed almost simultaneously. (With a
focal-plane shutter, the film frame is exposed gradually.) The lens
shutter synchronizes with the flash at virtually any shutter speed. It
is not suitable for single-lens reflex (SLR) cameras, however, because
each lens must have a built-in shutter unit and it requires a complex
camera mechanism. Recently, lens shutters have been used mainly in
compact cameras and in the lenses used with large-format cameras.
Mirror Cutoff
A slight darkening of the edge of the viewfinder image due to technical
limits on the size of the reflex mirror that may occur when using a
super-telephoto lens or bellows. Visible in the viewfinder image, not on
the film.
Mirror Lockup Function
Enables the photographer to manually raise the reflex mirror. Useful for
preventing camera shake caused by mirror movement (e.g., when a
telephoto lens is mounted on the camera). Available in selected camera
models.
Panning
Refers to following a subject with the camera and keeping it in the same
position in the viewfinder as it moves across (not towards or away from)
the field of view. Using a slow shutter speed and moving the camera in a
steady pan can help keep the subject relatively sharp, while the
background becomes a blur, thus emphasizing speed and movement.
Picture Angle
The amount of a scene that will be in the photo is expressed by the
degree of angle as the picture angle. Picture angle is determined by the
lens focal length and the camera''s picture format. Usually measured
across the diagonal of the picture frame, but sometimes expressed
according to vertical and horizontal measurements. Also called angle of
view.
Reflex Mirror
The mirror that reflects the light passing through the lens upward to
the prism for viewing. The front has a special coating and should not be
touched or cleaned without some precautions. In some cameras, the reflex
mirror can be locked in the up position.
Right-Angle Viewing Attachment (DR-3)
Accessory for the viewfinder eyepiece; enables viewing from a right
angle. Useful for copy stand work and when the camera is inconveniently
positioned low, near the ground, or at an angle which makes normal
viewing impossible. May be rotated for convenient viewing.
Self-Timer
Provides a delay of several seconds before the shutter is released. In
most cameras, a delay of around 10 seconds is common. Some cameras offer
a two-shot self-timer function that allows two successive shots. Other
cameras offer a variable number of shots. The self-timer function can
also be used to avoid camera shake.
Shutter Release Button
Fully depressed to release the shutter. With the latest cameras, lightly
pressing the button activates the exposures meter and starts autofocus
operation.
Spool
A cylinder with flanges at both ends for "taking up" roll film. Also
refers to the film take-up spindle.
Sprockets
Part of the film advance mechanism, these are the devices that engage
the film''s perforations. Rotating the sprocket wheel helps move the film
precisely.
Ultraviolet Photography
Taking pictures in invisible ultraviolet rays with wavelengths shorter
than 400nm. To perform ultraviolet photography, a special lens such as a
UV-Nikkor lens is required.
Viewfinder Magnification
Indicates the difference in the image size seen through the viewfinder
compared with that seen by the naked eye. Viewfinder magnification
depends on lens focal length and the focusing distance. With 35mm ...
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