| P |
|
| Panchromatic |
Photo
material that is sensitive to all colors that the human eye can
perceive. |
| Panning |
The
act of following a moving subject with the camera while releasing
the shutter. |
| Panoramic |
In
photography, an image proportionally more rectangular than a 35mm
film frame. Also, a type of camera for exposing film in a panoramic
format. |
| Parallax |
In
rangefinder cameras, the difference between the image seen by
the lens and the viewfinder. The discrepancy increases as the
subject moves closer to the camera. This does not occur in SLR
cameras |
| PC
Nikkor Lens |
A
specialized lens for architectural photography, with perspective
control through barrel lateral shifting relative to the film or
sensor plane, eliminating the need for the camera to be tilted,
to maintain vertical lines parallel, without converging or Keystoning. |
| Pentaprism |
A
prism in an SLR camera that allows the photographer to view
the image while it is being focused. |
| Perspective |
The
visual representation of three-dimensional space in a two dimensional
medium. Three dimensions are implied by converging lines and
a focal point. |
| Photoflood |
Tungsten
light source with a metal reflector. Typically either 5500K or
3200K. |
| Photography |
From
the Greek Photos and Graphos, light writing or writing
with light. The mix of art, craft and science for the creation
of images on a light sensitive surface (such as film or a CCD). |
| PICT |
A
Macintosh graphic imaging file format using a pct extension (*.pct).
May contain object-oriented and bitmapped graphics. |
| Pinhole
Camera |
A
camera with a fixed aperture made by poking a hole in a piece
of metal. Usually made from a small enclosed container such as
an oatmeal box or small tin. |
| Pixel |
Contraction
of Picture and Element. Any of the small discrete
elements that together constitute an image (as on a computer or
television screen or CRT), or any of the detecting elements of
a charge-coupled device used as an optical sensor in a digital
camera. Each one has a specific color and is contiguous to the
next to form a color image. |
| Plane |
An
imaginary line, flat area or field which lies perpendicular to
the optical axis. |
| Polarization |
Use
of polarizing filters to control the direction light travels.
The effects are minimizing glare and reflections and saturation
of colors, especially in landscapes. |
| Polarizing
Filter |
Two
pieces of polarizing material which rotate on an axis so that
the polarizing effect can be increased or decreased. |
| Portrait
Lens |
Usually
a lens with a moderately long focal length (80 to 135mm in 35mm
cameras). Sometimes they have slight diffusing glass. |
| Positive |
A
photo image in which the light areas correspond to light areas
in the subject, and the dark areas correspond to the shadow
areas in the subject. Also called a slide, transparency or color
reversal. |
| Posterization |
Banding
or lack of continuous tones in an image. Can be a deliberate
effect or, more commonly, a result of over-manipulation or compression
in a digital image. |
| PPI |
Pixels
per square inch. The greater the number, the better the image
quality. |
| Preset
Focus |
The
act of focusing at a predetermined distance to shoot a moving
subject as it goes by the focus point. A technique employed with
both manual lenses and when locking focus with auto lenses in
anticipation of fast moving subjects. Freeze Focus is a feature
by which the shutter is automatically actuated when the subject
reaches the preset focus point. |
| Primary
Colors |
Red,
yellow and blue, the three colors which combined make white light. |
| Prime
Lens |
A
lens with a single, fixed focal length; not a zoom lens. |
| Principal
Point |
A
point from where the focal length of the lens is measured. Normally
located at the center of the lens. However, compound lenses
have two principal points, and the location of these principal
points cannot be determined by appearance. |
| Prism |
A
piece of transparent material (i.e., glass or plastic) that is
capable of bending light. |
| Processing |
In
photography, chemical process where a latent photographic image
is converted to a stable visible image. |
| Projector |
A
device used to enlarge images by focusing light through them onto
a flat surface. |
| Pulling |
To
overexpose and underdevelop film to effectively reduce its speed. |
| Pushing |
To
underexpose and overdevelop film it to effectively increase its
speed. |
| |
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| Q |
|
| QVGA |
Quarter
Video Graphics Array. A reduced resolution of 320x240 pixels occupying
a very small amount of storage space. Practical size for capturing
sequences of 30fps. |
| Quasi-fisheye |
A
lens or lens attachment producing an image that covers the entire
frame.
A true fisheye lens circular image is completely within the frame.
|
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| R |
|
| RAM |
Temporary
computer memory, used to store data and software while in use. |
| Rangefinder |
A
camera with a viewfinder separate from the lens. Not a SLR. Also,
the usually built-in adjustable optical device for focusing a
camera that automatically indicates the correct focus (as when
two parts of a split image are brought together). |
| Raster |
Images
made of dots. Each individual one contains specific information
as to its size, color and position within the image. |
| Raw |
The RAW image format is the data from a digital camera as it comes
directly off the CCD, with no in-camera processing performed. |
| Rear
Focus |
The
focused area behind the subject. |
| Rear
Focusing System |
When
focusing, only the rear lens group moves. This eliminates the
changing of the physical length of the lens during focusing
and allows for faster focusing. (Refer also to Internal Focusing.)
|
| Rear
Sync |
In
this mode, the flash fires when the second curtain starts to move
across the frame, not the first one. When used in conjunction
with slow shutter speeds a trail of light is left giving by blur
effect the sensation of movement of a subject frozen by the flash.
|
| Reciprocity
Failure |
Photosensitive
materials require a linear sensitivity within a certain range.
Beyond that their sensitivity requires that exposure times be
increased in larger amounts than normal. |
| Recycling
Time |
The
time it takes for a strobe or battery-pack to recharge so that
it can power a flash burst. Shorter with fresh batteries and
when shooting in power saving mode P. |
| Red
Eye |
The
effect of red colored irises from subjects. It is caused by a
combination of factors, low ambient light asking the irises to
open more than regularly and small angle between the angles of
both the lens axis and that of the flash light. The light bouncing
from the back of the retinas brings back into the image the red
of the blood vessels. Big eyes don't help either. Red eye can
be reduced and even eliminated in several ways: by increasing
the ambient light, increasing the angle between the lens and the
flash beam with a bracket, having the subject look into a direction
other than the camera, or into a bright light, or simply by using
a flash with a red-eye system which pre-flashes to close down
the irises of the subject. |
| Reflected
Light Reading |
Light
meter reading made by pointing the meter towards the subject.
It will vary depending on the subject as different materials
reflect different amounts of light. |
| Reflector |
A
tool for redirecting light. Usually white or metallic, a cloth
or any light-reflecting board. |
| Reflex
Camera |
A
camera that uses a mirror to reflect light onto a ground glass
for viewing and focusing. |
| RGB |
Red,
Green and Blue. The three colors to which the human visual
system, digital cameras and many other devices are sensitive;
the colors used in displays and input devices. They represent
the additive color model, where 0% of each component yields black
and 100% of each component yields white. |
| Relative
Aperture |
Diameter
of the aperture divided by the focal length of the lens. Expressed
numerically as an f-stop. |
| Release-Priority
AF |
In
release-priority autofocus operation, the shutter can be released
at anytime whether the subject is in focus or not. Used in fast-moving
situations where you don't want to lose any of the action. |
| Repeating
Flash |
A
feature available in some units to make multiple flash bursts
during exposure. Useful for motion study in single frame multiple
exposure. Best used in dark studios in Bulb setting.
|
| Reproduction
Ratio |
The
size of the subject in an image compared to its actual size. As
a general rule, for subjects farther away than in macro photography,
the focal length of the lens used, divided by the camera to subject
distance yields the reproduction ratio. e.g. a 180mm lens focused
at 1.8 meters (18000mm) will have a 1:10 reproduction ratio.
|
| Resolution |
(Also
known as Resolving Power) The ability to reproduce small details
in a photograph. Resolving power is used to measure lens performance
using line pairs per millimeter (1/mm), and indicates how many
black pairs of lines placed at equal intervals within 1mm can
be resolved by a lens. |
| Retouching |
To
alter a finished print, digital image or piece of film in order
to cover up undesirable marks or elements. |
| Reversal
Materials |
Photo-sensitive
materials that when processed become positive images, i.e.,
slides and transparencies and certain print materials. |
| Ring
Flash |
A
circular-shaped electronic flash unit that fits around a lens
providing shadowless, uniform frontal lighting; especially useful
in close-up photography. |
| Rising
Front |
The
ability on a camera to raise the lens in relation to the film
to control focus and distortion. Usually only on large format
cameras. |
| Roll-Film |
Non-sheet
film. Film that comes in a roll and can be exposed in multiple
"frames." |
| Roll-Film
Adapter |
An
attachment for sheet film cameras that allows the use of roll
film. |
| |
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