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NSL Photography's™ Glossary of Photographic Terms - W
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White Balance
White balance is a function on the camera which allows it to compensate for different colors of light being emitted by different light sources.
Wide Angle Lens
In photography and cinematography, a wide-angle lens is a lens whose focal length is substantially shorter than the focal length of a normal lens for the image size produced by the camera, whether this is dictated by the dimensions of the image frame at the film plane for film cameras or the dimensions of the photosensor for digital cameras.
Many DSLR interchangeable lens cameras have photosensors which are smaller than the film format of full-frame 35 mm cameras. For the most part, the dimensions of these photosensors are similar to the APS-C image frame size, approximately 24 mm x 16 mm. Therefore, the angle of view for any given focal length lens will be narrower than it would be in a full-frame camera because the smaller sensor "sees" less of the image projected by the lens. The camera manufacturers provide a crop factor (sometimes called a field-of-view factor or a focal-length multiplier) to show how much smaller the sensor is than a full 35 mm film frame. For example, one common factor is 1.5 (Nikon DX format and some others) The 1.5 indicates that the angle of view of a lens on the camera is the same as that of a 1.5 times longer focal length on a 35 mm full-frame camera, which explains why the crop factor is also known as a focal-length multiplier. For example, a 28 mm lens on the DSLR (given a crop factor of 1.5) has the angle of view of a 42 mm lens on a full-frame camera.
Lens manufacturers have responded to this problem by making wide-angle lenses of much shorter focal lengths for these cameras, but in doing this, they limit the diameter of the image projected to slightly more than the diagonal measurement of the photosensor. This gives the designers more flexibility in providing the optical corrections necessary to economically produce high quality images at these short focal lengths, especially when the lenses are zoom lenses, however, these lenses cannot be used to light full 35mm sized sensors, such as the Nikon FX sensor.
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White Balance
White balance is a function on the camera which allows it to compensate for different colors of light being emitted by different light sources.
Wide Angle Lens
In photography and cinematography, a wide-angle lens is a lens whose focal length is substantially shorter than the focal length of a normal lens for the image size produced by the camera, whether this is dictated by the dimensions of the image frame at the film plane for film cameras or the dimensions of the photosensor for digital cameras.
Many DSLR interchangeable lens cameras have photosensors which are smaller than the film format of full-frame 35 mm cameras. For the most part, the dimensions of these photosensors are similar to the APS-C image frame size, approximately 24 mm x 16 mm. Therefore, the angle of view for any given focal length lens will be narrower than it would be in a full-frame camera because the smaller sensor "sees" less of the image projected by the lens. The camera manufacturers provide a crop factor (sometimes called a field-of-view factor or a focal-length multiplier) to show how much smaller the sensor is than a full 35 mm film frame. For example, one common factor is 1.5 (Nikon DX format and some others) The 1.5 indicates that the angle of view of a lens on the camera is the same as that of a 1.5 times longer focal length on a 35 mm full-frame camera, which explains why the crop factor is also known as a focal-length multiplier. For example, a 28 mm lens on the DSLR (given a crop factor of 1.5) has the angle of view of a 42 mm lens on a full-frame camera.
Lens manufacturers have responded to this problem by making wide-angle lenses of much shorter focal lengths for these cameras, but in doing this, they limit the diameter of the image projected to slightly more than the diagonal measurement of the photosensor. This gives the designers more flexibility in providing the optical corrections necessary to economically produce high quality images at these short focal lengths, especially when the lenses are zoom lenses, however, these lenses cannot be used to light full 35mm sized sensors, such as the Nikon FX sensor.
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NSL Photography's™ Glossary of Photographic Terms - V
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Variable Focus Lens
Lens of which the focal length can be continuously varied between set limits. The lens must be refocused with each change in focal length.
Vibration Reduction (Image Stabilization)
With still cameras, camera shake is particularly problematic at slow shutter speeds or with long focal length (telephoto) lenses. Vibration reduction (image stabilization) is a mechanism used in a camera that stabilizes the recorded image by varying the optical path to the sensor. Stabilization for SLR and DSLR cameras is usually performed by the lens. Many digital point and shoot cameras also have image stabilization, but performed in the camera itself.
Image stabilization can often permit the use of shutter speeds 2–4 stops slower (exposures 4–16 times longer) than a person can normally accomplish hand holding a camera, for any particular lens/camera combination, although even slower effective speeds have been reported.
Some image stabilized lenses have an "Active Mode" intended to be used when shooting from a moving vehicle, such as a car or boat, to correct for larger shakes than the "Normal Mode."
Viewfinder
Device or system indicating the field of view encompassed by the camera lens. The term is sometimes used as a description of the type of camera that does not use reflex or "straight-through" viewing systems and therefore has to have a separate viewfinder.
Vignetting
Underexposure of image corners produced deliberately by shading or unintentionally by inappropriate equipment, such as unsuitable lens hood or badly designed lens. A common fault of wide-angle lenses, owing to reflection cut-off, etc. of some of the very oblique rays.
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Variable Focus Lens
Lens of which the focal length can be continuously varied between set limits. The lens must be refocused with each change in focal length.
Vibration Reduction (Image Stabilization)
With still cameras, camera shake is particularly problematic at slow shutter speeds or with long focal length (telephoto) lenses. Vibration reduction (image stabilization) is a mechanism used in a camera that stabilizes the recorded image by varying the optical path to the sensor. Stabilization for SLR and DSLR cameras is usually performed by the lens. Many digital point and shoot cameras also have image stabilization, but performed in the camera itself.
Image stabilization can often permit the use of shutter speeds 2–4 stops slower (exposures 4–16 times longer) than a person can normally accomplish hand holding a camera, for any particular lens/camera combination, although even slower effective speeds have been reported.
Some image stabilized lenses have an "Active Mode" intended to be used when shooting from a moving vehicle, such as a car or boat, to correct for larger shakes than the "Normal Mode."
Viewfinder
Device or system indicating the field of view encompassed by the camera lens. The term is sometimes used as a description of the type of camera that does not use reflex or "straight-through" viewing systems and therefore has to have a separate viewfinder.
Vignetting
Underexposure of image corners produced deliberately by shading or unintentionally by inappropriate equipment, such as unsuitable lens hood or badly designed lens. A common fault of wide-angle lenses, owing to reflection cut-off, etc. of some of the very oblique rays.
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NSL Photography's™ Glossary of Photographic Terms - U
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UD
Ultra Low dispersion lens, pls refer to ED, LD sections.
Ultra-wide angle lens
Extra wide angle lens are those with an angle of view greater than 90°. For 35 mm cameras the description usually applies to lenses of shorter focal length than about 24 mm.
Underexposure
A condition in which too little light reaches the film, producing a thin negative, dark slide, dark image, or muddy-looking print.
Unipod (Monopod)
A one-legged support used to hold the camera steady.
UV
The ultra violet light. This is beyond the visible spectrum i.e. it's invisible electromagnetic radiation of the sunlight.
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UD
Ultra Low dispersion lens, pls refer to ED, LD sections.
Ultra-wide angle lens
Extra wide angle lens are those with an angle of view greater than 90°. For 35 mm cameras the description usually applies to lenses of shorter focal length than about 24 mm.
Underexposure
A condition in which too little light reaches the film, producing a thin negative, dark slide, dark image, or muddy-looking print.
Unipod (Monopod)
A one-legged support used to hold the camera steady.
UV
The ultra violet light. This is beyond the visible spectrum i.e. it's invisible electromagnetic radiation of the sunlight.
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NSL Photography's™ Glossary of Photographic Terms - T
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Tear Sheets
Tear sheets refer to ads taken out of the pages of magazines, newspapers and other printed matter. Any time work is published, the author gets copies, often literally clipped out of copies of the magazine, for their own future advertising and portfolio. Tear sheets provide evidence that the authors work has been published. Tear sheets are similar in this regard to reprints of articles.
Tear sheets got their name since it used to be common for magazines to rip up a few issues and send the pages torn out to authors, photographers, etc.
Teleconverter
A teleconverter is a secondary lens which is mounted between the camera and a photographic lens. Its job is to enlarge the image obtained by the original lens. Teleconverters are typically made in 1.4x, 1.7x, 2x and 3x models. The use of a 2x teleconverter gives the effect of using lens with twice the focal length. It also decreases the intensity of the light reaching the film by a factor of 4 (an equivalent of doubling the focal ratio) as well as the resolution (by a factor of 2).
Tear sheets got their name since it used to be common for magazines to rip up a few issues and send the pages torn out to authors, photographers, etc.
Telephoto Lens
In photography, a telephoto lens has a specific construction of a long focal length lens in which the physical length of the lens is shorter than the focal length. In these lenses the optical center lies outside of its physical construction, so that the entire lens assembly is between the optical center and the focal plane. A regular lens of a focal length that is longer than what is considered a normal lens is not necessarily a telephoto lens. A telephoto lens has to incorporate a special lens group known as a telephoto group, nevertheless, non-telephoto lenses of long focal length are often informally referred to as telephoto lenses. The angle of view created by a telephoto lens is the same as that created by an ordinary lens of the same specified focal length.
Telephoto and other long focal length lenses are best known for making distant objects appear magnified. This effect is similar to moving closer to the object, but is not the same, since perspective is a function solely of viewing location. Two images taken from the same location, one with a wide angle lens and the other with a telephoto lens, will show identical perspective, in that near and far objects appear the same relative size to each other. Comparing magnification by using a long lens to magnification by moving closer, however, the telephoto shot appears to compress the distance between objects due to the perspective from the more distant location.
Through the Lens (TTL)
Type of exposure meter built into the camera body and reading through the camera lens. May measure either at full aperture or at picture taking aperture.
Through the Lens Focusing
Viewing a scene to be photographed through the same lens that admits light to the film or sensor. Through the lens viewing, as in an SLR or DSLR camera, while focusing and composing a picture, eliminates parallax.
Through the Lens Metering
Meter built into the camera to determine exposure for the scene by reading light that passes through the lens. SLR and DSLR cameras have built-in meters which measure light after it has passed through the lens, a feature that enables exposure readings to be taken from the actual image about to be recorded, whatever the lens angle of view and regardless of whether a filter is used or not.
Time Exposure
A comparatively long exposure made in seconds or minutes.
TLR
Twin lens reflex camera that has separate viewing and actual exposure lenses.
Transparency
Slide film.
Tripod
A three-legged supporting stand used to hold the camera steady. Especially useful when using slow shutter speeds, macro and telephoto lenses.
Tungsten Light
Light from regular room lamps and ceiling fixtures, not fluorescent. Images produced under this light source can be extremely warm.
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Tear Sheets
Tear sheets refer to ads taken out of the pages of magazines, newspapers and other printed matter. Any time work is published, the author gets copies, often literally clipped out of copies of the magazine, for their own future advertising and portfolio. Tear sheets provide evidence that the authors work has been published. Tear sheets are similar in this regard to reprints of articles.
Tear sheets got their name since it used to be common for magazines to rip up a few issues and send the pages torn out to authors, photographers, etc.
Teleconverter
A teleconverter is a secondary lens which is mounted between the camera and a photographic lens. Its job is to enlarge the image obtained by the original lens. Teleconverters are typically made in 1.4x, 1.7x, 2x and 3x models. The use of a 2x teleconverter gives the effect of using lens with twice the focal length. It also decreases the intensity of the light reaching the film by a factor of 4 (an equivalent of doubling the focal ratio) as well as the resolution (by a factor of 2).
Tear sheets got their name since it used to be common for magazines to rip up a few issues and send the pages torn out to authors, photographers, etc.
Telephoto Lens
In photography, a telephoto lens has a specific construction of a long focal length lens in which the physical length of the lens is shorter than the focal length. In these lenses the optical center lies outside of its physical construction, so that the entire lens assembly is between the optical center and the focal plane. A regular lens of a focal length that is longer than what is considered a normal lens is not necessarily a telephoto lens. A telephoto lens has to incorporate a special lens group known as a telephoto group, nevertheless, non-telephoto lenses of long focal length are often informally referred to as telephoto lenses. The angle of view created by a telephoto lens is the same as that created by an ordinary lens of the same specified focal length.
Telephoto and other long focal length lenses are best known for making distant objects appear magnified. This effect is similar to moving closer to the object, but is not the same, since perspective is a function solely of viewing location. Two images taken from the same location, one with a wide angle lens and the other with a telephoto lens, will show identical perspective, in that near and far objects appear the same relative size to each other. Comparing magnification by using a long lens to magnification by moving closer, however, the telephoto shot appears to compress the distance between objects due to the perspective from the more distant location.
Through the Lens (TTL)
Type of exposure meter built into the camera body and reading through the camera lens. May measure either at full aperture or at picture taking aperture.
Through the Lens Focusing
Viewing a scene to be photographed through the same lens that admits light to the film or sensor. Through the lens viewing, as in an SLR or DSLR camera, while focusing and composing a picture, eliminates parallax.
Through the Lens Metering
Meter built into the camera to determine exposure for the scene by reading light that passes through the lens. SLR and DSLR cameras have built-in meters which measure light after it has passed through the lens, a feature that enables exposure readings to be taken from the actual image about to be recorded, whatever the lens angle of view and regardless of whether a filter is used or not.
Time Exposure
A comparatively long exposure made in seconds or minutes.
TLR
Twin lens reflex camera that has separate viewing and actual exposure lenses.
Transparency
Slide film.
Tripod
A three-legged supporting stand used to hold the camera steady. Especially useful when using slow shutter speeds, macro and telephoto lenses.
Tungsten Light
Light from regular room lamps and ceiling fixtures, not fluorescent. Images produced under this light source can be extremely warm.
If you have any suggested additions or corrections to the Glossary, please contact us.
NSL Photography's™ Glossary of Photographic Terms - S
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Safelight
An enclosed darkroom lamp fitted with a filter to screen out light rays to which film and paper are sensitive.
Saturation
An attribute of perceived color, or the percentage of hue in a color. Saturated colors are called vivid, strong, or deep. Desaturated colors are called dull, weak, or washed out.
Scale
Focusing method consisting of set of marks to indicate distances at which a lens is focused. May be engraved around the lens barrel, on the focusing control or on the camera body.
Screen
In a camera. the surface upon which the lens projects an image for viewfinding and, usually, focusing purposes.
Selective Focus
Choosing a lens opening that produces a shallow depth of field. Usually this is used to isolate a subject by causing most other elements in the scene to be blurred.
Self-Timer
Mechanism delaying the opening of the shutter for some seconds after the release has been operated.
Semi-Automatic Iris
Diaphragm mechanism which closes down to the taking aperture when the shutter is released, but must be manually re-opened to full aperture.
Sensitivity
Expression of the nature of a photographic emulsion's or digital camera's sensor response to light. Can be concerned with degree of sensitivity as expressed by film speed or response to light of various colors (spectral sensitivity).
Sharpness
A term used to describe the ability of a lens to render fine detail clearly. It is dependent on the contrast and resolution of a lens and varies with the f/stop. Generally a lens is sharpest at the middle apertures. Technically it can be explained as clarity of the photographic image in terms of focus and contrast.
Shutter
Blades, a curtain, plate, or some other movable cover in a camera that controls the time during which light reaches the film.
Shutter Speed
In photography, shutter speed is a common term used to discuss exposure time, the effective length of time a shutter is open. The total exposure is proportional to this exposure time, or duration of light reaching the film or image sensor.
Shutter Priority
An exposure mode on an automatic or autofocus camera that lets you select the desired shutter speed; the camera sets the aperture for proper exposure. If you change the shutter speed, or the light level changes, the camera adjusts the aperture automatically.
Sidelighting
Light striking the subject from the side relative to the position of the camera, producing shadows and highlights to create modeling on the subject.
Single Servo AF
Once the subject is in focus, focus is locked. Useful for recomposing the picture.
Single Lens Reflex (SLR) or Digital Single Lens Reflex Camera
Types of cameras which allow you to see through the camera's lens as you look in the camera's viewfinder. Other camera functions, such as light metering and flash control, also operate through the camera's lens, as well.
Slave Unit
Accessory flash "slave" units are available to fire multiple flash units without multiple electrical connections to the camera.
Slow Sync
A flash technique for using the flash at a slow shutter speed. Flash shooting in dim light or at night at a fast shutter speed often results in a flash-illuminated subject against a dark background. Using a slower shutter speed with the flash brings out the background details in the picture. Use of a slow shutter speed with Rear-Curtain Sync is particularly effective for illustrating the movement of a stream of light. Can be of very creative if put to good use.
Slide
A photographic transparency (positive) mounted for projection.
SLR
The SLR or single lens reflex camera uses an automatic moving mirror system which permits the photographer to see exactly what will be captured by the film, as opposed to a non-SLR camera where the view through the viewfinder could be significantly different from what was captured on film.
Prior to the development of SLR, all cameras with viewfinders had two optical light paths, one path through the lens to the film, and another path positioned above (twin lens reflex) or to the side (rangefinder). Because the viewfinder and the film lens cannot share the same optical path, the viewing lens is aimed to intersect with the film lens at a fixed point somewhere in front of the camera. This is not problematic for pictures taken at a middle or longer distance but parallax causes framing errors in close-up shots. Moreover, focusing the lens of a non-reflex camera when it is opened to wider apertures, such as in low light or while using low-speed film, is not easy.
Soft Focus
Produced by use of a special lens that creates soft outlines. Filters are more popular than lens as it is more economical and flexible.
Soft Lighting
Lighting that is low or moderate in contrast, such as on an overcast day.
Split-Image
Form of rangefinder image, bisected so that the two halves of the image are aligned only when the lens is correctly focused.
Spot Metering Spot metering, used to get accurate light readings of a small part of a subject, uses exposure metering with a narrow angle of view, typically less than 5 percent of the viewing area, to measure light within limited areas to determine the exposure for a photograph.
Stopping Down
Changing the lens aperture to a smaller opening; for example, from f/8 to f/11.
Sync Cords
The purpose of sync cords is to allow the camera to control the flash, so the flash fires at the correct time. Other common names for electrical cords to connect flash to camera are PC cord, sync cord and synch cord.
Sync Socket
Often called "PC terminal" or "PC Socket." A socket in the camera to which the sync cord is plugged in.
Sync Speed
Exposure time with a focal-plane shutter is measured from the instant the first curtain is released, to begin its travel across the frame, until the instant the second curtain is released, to begin its travel across the frame.
Synchronization
The action of shutter opening and closing of electrical contacts to fire a flash at the correct moment to make most efficient use of the light output.
If you have any suggested additions or corrections to the Glossary, please contact us.
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Safelight
An enclosed darkroom lamp fitted with a filter to screen out light rays to which film and paper are sensitive.
Saturation
An attribute of perceived color, or the percentage of hue in a color. Saturated colors are called vivid, strong, or deep. Desaturated colors are called dull, weak, or washed out.
Scale
Focusing method consisting of set of marks to indicate distances at which a lens is focused. May be engraved around the lens barrel, on the focusing control or on the camera body.
Screen
In a camera. the surface upon which the lens projects an image for viewfinding and, usually, focusing purposes.
Selective Focus
Choosing a lens opening that produces a shallow depth of field. Usually this is used to isolate a subject by causing most other elements in the scene to be blurred.
Self-Timer
Mechanism delaying the opening of the shutter for some seconds after the release has been operated.
Semi-Automatic Iris
Diaphragm mechanism which closes down to the taking aperture when the shutter is released, but must be manually re-opened to full aperture.
Sensitivity
Expression of the nature of a photographic emulsion's or digital camera's sensor response to light. Can be concerned with degree of sensitivity as expressed by film speed or response to light of various colors (spectral sensitivity).
Sharpness
A term used to describe the ability of a lens to render fine detail clearly. It is dependent on the contrast and resolution of a lens and varies with the f/stop. Generally a lens is sharpest at the middle apertures. Technically it can be explained as clarity of the photographic image in terms of focus and contrast.
Shutter
Blades, a curtain, plate, or some other movable cover in a camera that controls the time during which light reaches the film.
Shutter Speed
In photography, shutter speed is a common term used to discuss exposure time, the effective length of time a shutter is open. The total exposure is proportional to this exposure time, or duration of light reaching the film or image sensor.
Shutter Priority
An exposure mode on an automatic or autofocus camera that lets you select the desired shutter speed; the camera sets the aperture for proper exposure. If you change the shutter speed, or the light level changes, the camera adjusts the aperture automatically.
Sidelighting
Light striking the subject from the side relative to the position of the camera, producing shadows and highlights to create modeling on the subject.
Single Servo AF
Once the subject is in focus, focus is locked. Useful for recomposing the picture.
Single Lens Reflex (SLR) or Digital Single Lens Reflex Camera
Types of cameras which allow you to see through the camera's lens as you look in the camera's viewfinder. Other camera functions, such as light metering and flash control, also operate through the camera's lens, as well.
Slave Unit
Accessory flash "slave" units are available to fire multiple flash units without multiple electrical connections to the camera.
Slow Sync
A flash technique for using the flash at a slow shutter speed. Flash shooting in dim light or at night at a fast shutter speed often results in a flash-illuminated subject against a dark background. Using a slower shutter speed with the flash brings out the background details in the picture. Use of a slow shutter speed with Rear-Curtain Sync is particularly effective for illustrating the movement of a stream of light. Can be of very creative if put to good use.
Slide
A photographic transparency (positive) mounted for projection.
SLR
The SLR or single lens reflex camera uses an automatic moving mirror system which permits the photographer to see exactly what will be captured by the film, as opposed to a non-SLR camera where the view through the viewfinder could be significantly different from what was captured on film.
Prior to the development of SLR, all cameras with viewfinders had two optical light paths, one path through the lens to the film, and another path positioned above (twin lens reflex) or to the side (rangefinder). Because the viewfinder and the film lens cannot share the same optical path, the viewing lens is aimed to intersect with the film lens at a fixed point somewhere in front of the camera. This is not problematic for pictures taken at a middle or longer distance but parallax causes framing errors in close-up shots. Moreover, focusing the lens of a non-reflex camera when it is opened to wider apertures, such as in low light or while using low-speed film, is not easy.
Soft Focus
Produced by use of a special lens that creates soft outlines. Filters are more popular than lens as it is more economical and flexible.
Soft Lighting
Lighting that is low or moderate in contrast, such as on an overcast day.
Split-Image
Form of rangefinder image, bisected so that the two halves of the image are aligned only when the lens is correctly focused.
Spot Metering Spot metering, used to get accurate light readings of a small part of a subject, uses exposure metering with a narrow angle of view, typically less than 5 percent of the viewing area, to measure light within limited areas to determine the exposure for a photograph.
Stopping Down
Changing the lens aperture to a smaller opening; for example, from f/8 to f/11.
Sync Cords
The purpose of sync cords is to allow the camera to control the flash, so the flash fires at the correct time. Other common names for electrical cords to connect flash to camera are PC cord, sync cord and synch cord.
Sync Socket
Often called "PC terminal" or "PC Socket." A socket in the camera to which the sync cord is plugged in.
Sync Speed
Exposure time with a focal-plane shutter is measured from the instant the first curtain is released, to begin its travel across the frame, until the instant the second curtain is released, to begin its travel across the frame.
Synchronization
The action of shutter opening and closing of electrical contacts to fire a flash at the correct moment to make most efficient use of the light output.
If you have any suggested additions or corrections to the Glossary, please contact us.
NSL Photography's™ Glossary of Photographic Terms - R
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Rangefinder
Instrument for measuring distances from a given point, usually based on slightly separated views of the scene provided by mirrors or prisms.
Raw Image File
A raw image file contains minimally processed data from the image sensor of a digital camera. Raw file images are not yet processed and therefore are not ready to be used with a bitmap graphics editor or printed. Normally, the image is processed by a raw converter in a wide-gamut internal colorspace where precise adjustments can be made before conversion to a film format such as TIFF, PSD or JPEG (JPG) for storage, printing, web display or further manipulation, which often encodes the image in a device-dependent colorspace.
Raw image files are sometimes called digital negatives, as they fulfill the same role as negatives in film photography, that is, the negative is not directly usable as an image, but has all of the information needed to create an image.
Like a photographic negative, a raw digital image may have a wider dynamic range or color gamut than the eventual final image format, and is usually the one "closest" to the real picture as it preserves the most of its details. The raw image format's purpose is to faithfully record both 100% of exactly what the sensor "saw" or "sensed" (the data), and the conditions surrounding the recording of the image (the metadata).
Rear-Curtain Sync
Flash fires an instant before the second (rear) curtain of the focal plane shutter begins to move. When slow shutter speeds are used, this feature can create a blur effect from the ambient light, i.e., a flowing- light patterns following a moving subject with subject movement frozen at the end of the light flow.
Reciprocity Failure
This occurs for photographic emulsions (film) when exposure times are beyond the film's normal range. As exposure times increase, more light, and/or more intensive light is required in addition to the expected amount, to properly expose the film to achieve the desired result.
Rectilinear lens
This is a photographic lens which produces images where the straight lines of the subject, such as building walls, appear straight, not curved. These lenses have little barrel or pincushion distortion. The majority of still camera lenses produce nearly rectilinear images.
Refractive Index
A technical term used to describe the effect of a lens in causing light rays to bend.
Reflector
Any device used to reflect light onto a subject to improve balance of exposure (contrast). Another way is to use fill in flash.
Relative Aperture
Numerical expression of effective aperture, also known as f-number. It's obtained by dividing focal length by diameter of effective aperture.
Remote Shutter Release
A mechanical or electronic device which attaches to a camera for the purpose of activating the shutter of the camera without touching the camera, to eliminate shaking the camera from the physical action of pressing the shutter release button. Remote shutter releases may vary from a simple physical cable which presses down on the shutter release button, to an electronic remote shutter release which can both delay the shutter release for a set period of time, and keep the shutter open for a set period of time.
Resolution
The ability of a lens to discern small detail. In photography, the image resolution in the final photograph depends on the resolving power of the film or the sensor, and of that of the lens. The two are not related, but the effective resolution is a function of both.
Retouching
Altering a print, image or negative after development by use of dyes or pencils software, to alter tones of highlights, shadows, and other details, or to remove blemishes.
RGB
Red, green & blue, where black is simulated color. CMYK is the four primary colors.
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Rangefinder
Instrument for measuring distances from a given point, usually based on slightly separated views of the scene provided by mirrors or prisms.
Raw Image File
A raw image file contains minimally processed data from the image sensor of a digital camera. Raw file images are not yet processed and therefore are not ready to be used with a bitmap graphics editor or printed. Normally, the image is processed by a raw converter in a wide-gamut internal colorspace where precise adjustments can be made before conversion to a film format such as TIFF, PSD or JPEG (JPG) for storage, printing, web display or further manipulation, which often encodes the image in a device-dependent colorspace.
Raw image files are sometimes called digital negatives, as they fulfill the same role as negatives in film photography, that is, the negative is not directly usable as an image, but has all of the information needed to create an image.
Like a photographic negative, a raw digital image may have a wider dynamic range or color gamut than the eventual final image format, and is usually the one "closest" to the real picture as it preserves the most of its details. The raw image format's purpose is to faithfully record both 100% of exactly what the sensor "saw" or "sensed" (the data), and the conditions surrounding the recording of the image (the metadata).
Rear-Curtain Sync
Flash fires an instant before the second (rear) curtain of the focal plane shutter begins to move. When slow shutter speeds are used, this feature can create a blur effect from the ambient light, i.e., a flowing- light patterns following a moving subject with subject movement frozen at the end of the light flow.
Reciprocity Failure
This occurs for photographic emulsions (film) when exposure times are beyond the film's normal range. As exposure times increase, more light, and/or more intensive light is required in addition to the expected amount, to properly expose the film to achieve the desired result.
Rectilinear lens
This is a photographic lens which produces images where the straight lines of the subject, such as building walls, appear straight, not curved. These lenses have little barrel or pincushion distortion. The majority of still camera lenses produce nearly rectilinear images.
Refractive Index
A technical term used to describe the effect of a lens in causing light rays to bend.
Reflector
Any device used to reflect light onto a subject to improve balance of exposure (contrast). Another way is to use fill in flash.
Relative Aperture
Numerical expression of effective aperture, also known as f-number. It's obtained by dividing focal length by diameter of effective aperture.
Remote Shutter Release
A mechanical or electronic device which attaches to a camera for the purpose of activating the shutter of the camera without touching the camera, to eliminate shaking the camera from the physical action of pressing the shutter release button. Remote shutter releases may vary from a simple physical cable which presses down on the shutter release button, to an electronic remote shutter release which can both delay the shutter release for a set period of time, and keep the shutter open for a set period of time.
Resolution
The ability of a lens to discern small detail. In photography, the image resolution in the final photograph depends on the resolving power of the film or the sensor, and of that of the lens. The two are not related, but the effective resolution is a function of both.
Retouching
Altering a print, image or negative after development by use of dyes or pencils software, to alter tones of highlights, shadows, and other details, or to remove blemishes.
RGB
Red, green & blue, where black is simulated color. CMYK is the four primary colors.
If you have any suggested additions or corrections to the Glossary, please contact us.
NSL Photography's™ Glossary of Photographic Terms - Q
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NSL Photography's™ Glossary of Photographic Terms - P
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Pan (Panchromatic)
Designation of films that record all colors in tones of about the same relative brightness as the human eye sees in the original scene, sensitive to all visible wave-lengths.
Panning
Moving the camera so that the image of a moving object remains in the same relative position in the viewfinder as you take a picture. The eventual effect creates a strong sense of movement.
Panorama
A broad view, usually scenic.
Parallax (Camera)
Parallax is the difference between what the viewfinder sees and what the camera records, especially at close distances. This is caused by the separation between the viewfinder and the picture-taking lens. There is no parallax with SLR and DSLR cameras because when you look through the viewfinder, you are viewing the subject through the camera's lens.
Parallax (Panorama)
Parallax is an optical illusion in which things near to us appear to move faster than things farther away. When you're shooting a panorama, parallax is exhibited when you rotate your camera and objects nearer the lens will appear to shift left or right in relation to objects further from the lens and in the background. Parallax problems can be eliminated or certainly mitigated by setting the rotational axis of the camera directly over the center of the lens Entrance Pupil of the lens attached to the camera.
PC
Personal Computer.
PC Cords
PC cords or sync cords allow the camera to control the flash, so the flash fires at the correct time.
Perforations
Regularly and accurately spaced holes punched throughout the length of film for still cameras. Basically the perforation function as a guide for precision registration of film and also provide mechanical movement from frame to frame.
Perspective
The rendition of apparent space in a flat photograph, i.e., how far the foreground and background appear to be separated from each other. The rendition of perspective is determined by the camera-to-subject distance. If objects appear in their normal size relations, the perspective is considered "normal." If the foreground objects are much larger than the ones in the background, the perspective is considered "exaggerated," and when there is little difference in size between foreground and background, we say the perspective looks "compressed."
Perspective Control
Perspective control lenses are also known as tilt or shift lenses. These lenses permit the correction of linear distortion resulting from high or low camera angle. Most use a gear or sliding mechanism and require manual metering.
Photomicrography
The process of taking photographs of minute objects using a camera and a microscope, not to be confused with "microphotography," the process of making minute photographs of large objects.
Photoshopping
Photoshopping is slang terminology describing the digital editing of photos. The term has its origin from Adobe Systems Incorported "Photoshop" product, the most commonly used photographic image editor by most professionals for this purpose. While Adobe Systems Incorporated discourages use of the term "photoshopping" as a verb, due to their concern that it may undermine the company's trademark of the word "Photoshop," is remains widely used, and sometimes a negative one, to the chagrin of Adobe.
Picture Angle
The angle of coverage of a lens usually measured across the diagonal of the picture frame. It varies with focal length. The longer the focal length, the narrower the picture angle, the shorter the focal length, the wider the picture angle.
Pincushion Distortion
The opposite of barrel distortion, it is when straight lines are bowed in toward the middle to resemble the sides of a pincushion. It is present in small amounts in some telephoto and telephoto-zoom lenses.
Pixel
In digital imaging, a pixel is the smallest item of information in an image. Pixels are usually arranged in a 2-dimensional grid, and are generally represented by dots or squares. Each pixel is a piece of an original image, where together they provide an accurate representation of the original image. The intensity of each pixel is variable. In color imaging, each pixel has typically three or four components such as red, green, and blue, or cyan, magenta, yellow, and black, to produce the correct color of that point in the image.
Plane
Level surface. It's used in photography chiefly in respect to focal plane, an imaginary level surface perpendicular to the lens axis in which the lens is intended to form an image. When the camera is loaded, the focal plane is occupied by the film or sensor surface.
Point & Shoot Camera (P&S)
A point and shoot camera, also called a compact camera, is a still camera designed primarily for simple operation. Most of them use autofocus or focus free lenses for focusing, and have automatic systems for setting the exposure options, plus have built-in flash units.
Point and shoots are by far the best selling type of camera. They are popular with people who don’t consider themselves photographers, yet want an easy to use camera for vacations, parties, and other events.
Point and shoot cameras are distinguished from single lens reflex cameras (SLRs and DSLRs) in many respects. The image that the photographer sees through the viewfinder of a point and shoot camera is not the same image that passes through the primary lens of the camera. Rather, the image in the viewfinder passes through a separate lens. Digital point and shoot cameras eliminated the need for the SLR design to some degree, by previewing the photo on the camera's LCD electronically via the lens. Point and shoot cameras don't have interchangeable lenses.
Polarizing Filter
A filter that transmits light traveling in one plane while absorbing light traveling in other planes. When placed on a camera lens or on light sources, it can eliminate undesirable reflections from a subject such as water, glass, or other objects with shiny surfaces. This filter also darkens blue sky.
Polarized Light
Light waves vibrating in one plane only as opposed to the multi-directional vibrations of normal rays. Natural effect produced by some reflecting surfaces, such as glass, water, polished wood, etc., but it can also be simulated by placing a special screen in front of the light source. The transmission of polarized light is restrained by using a screen at an angle to the plane of polarization.
Preset Iris
Diaphragm with two setting rings or one ring that can be moved to two positions. One is click-stopped, but does not affect the iris, the other moves freely and alters the aperture. The required aperture is preset on the first ring, and the iris closed down with the second just before exposure.
Prime Lens
A lens with a fixed focal length.
Program Exposure
An exposure mode on an automatic or autofocus camera which automatically sets both the aperture and the shutter speed for proper exposure. On some digital cameras it can set the ISO as well.
Programmed Auto
Camera sets both shutter speed and aperture for correct exposure and on some digital cameras it can set the ISO as well.
If you have any suggested additions or corrections to the Glossary, please contact us.
# A B C D E F G H I J K L M
N O P Q R S T U V W X Y Z
Pan (Panchromatic)
Designation of films that record all colors in tones of about the same relative brightness as the human eye sees in the original scene, sensitive to all visible wave-lengths.
Panning
Moving the camera so that the image of a moving object remains in the same relative position in the viewfinder as you take a picture. The eventual effect creates a strong sense of movement.
Panorama
A broad view, usually scenic.
Parallax (Camera)
Parallax is the difference between what the viewfinder sees and what the camera records, especially at close distances. This is caused by the separation between the viewfinder and the picture-taking lens. There is no parallax with SLR and DSLR cameras because when you look through the viewfinder, you are viewing the subject through the camera's lens.
Parallax (Panorama)
Parallax is an optical illusion in which things near to us appear to move faster than things farther away. When you're shooting a panorama, parallax is exhibited when you rotate your camera and objects nearer the lens will appear to shift left or right in relation to objects further from the lens and in the background. Parallax problems can be eliminated or certainly mitigated by setting the rotational axis of the camera directly over the center of the lens Entrance Pupil of the lens attached to the camera.
PC
Personal Computer.
PC Cords
PC cords or sync cords allow the camera to control the flash, so the flash fires at the correct time.
Perforations
Regularly and accurately spaced holes punched throughout the length of film for still cameras. Basically the perforation function as a guide for precision registration of film and also provide mechanical movement from frame to frame.
Perspective
The rendition of apparent space in a flat photograph, i.e., how far the foreground and background appear to be separated from each other. The rendition of perspective is determined by the camera-to-subject distance. If objects appear in their normal size relations, the perspective is considered "normal." If the foreground objects are much larger than the ones in the background, the perspective is considered "exaggerated," and when there is little difference in size between foreground and background, we say the perspective looks "compressed."
Perspective Control
Perspective control lenses are also known as tilt or shift lenses. These lenses permit the correction of linear distortion resulting from high or low camera angle. Most use a gear or sliding mechanism and require manual metering.
Photomicrography
The process of taking photographs of minute objects using a camera and a microscope, not to be confused with "microphotography," the process of making minute photographs of large objects.
Photoshopping
Photoshopping is slang terminology describing the digital editing of photos. The term has its origin from Adobe Systems Incorported "Photoshop" product, the most commonly used photographic image editor by most professionals for this purpose. While Adobe Systems Incorporated discourages use of the term "photoshopping" as a verb, due to their concern that it may undermine the company's trademark of the word "Photoshop," is remains widely used, and sometimes a negative one, to the chagrin of Adobe.
Picture Angle
The angle of coverage of a lens usually measured across the diagonal of the picture frame. It varies with focal length. The longer the focal length, the narrower the picture angle, the shorter the focal length, the wider the picture angle.
Pincushion Distortion
The opposite of barrel distortion, it is when straight lines are bowed in toward the middle to resemble the sides of a pincushion. It is present in small amounts in some telephoto and telephoto-zoom lenses.
Pixel
In digital imaging, a pixel is the smallest item of information in an image. Pixels are usually arranged in a 2-dimensional grid, and are generally represented by dots or squares. Each pixel is a piece of an original image, where together they provide an accurate representation of the original image. The intensity of each pixel is variable. In color imaging, each pixel has typically three or four components such as red, green, and blue, or cyan, magenta, yellow, and black, to produce the correct color of that point in the image.
Plane
Level surface. It's used in photography chiefly in respect to focal plane, an imaginary level surface perpendicular to the lens axis in which the lens is intended to form an image. When the camera is loaded, the focal plane is occupied by the film or sensor surface.
Point & Shoot Camera (P&S)
A point and shoot camera, also called a compact camera, is a still camera designed primarily for simple operation. Most of them use autofocus or focus free lenses for focusing, and have automatic systems for setting the exposure options, plus have built-in flash units.
Point and shoots are by far the best selling type of camera. They are popular with people who don’t consider themselves photographers, yet want an easy to use camera for vacations, parties, and other events.
Point and shoot cameras are distinguished from single lens reflex cameras (SLRs and DSLRs) in many respects. The image that the photographer sees through the viewfinder of a point and shoot camera is not the same image that passes through the primary lens of the camera. Rather, the image in the viewfinder passes through a separate lens. Digital point and shoot cameras eliminated the need for the SLR design to some degree, by previewing the photo on the camera's LCD electronically via the lens. Point and shoot cameras don't have interchangeable lenses.
Polarizing Filter
A filter that transmits light traveling in one plane while absorbing light traveling in other planes. When placed on a camera lens or on light sources, it can eliminate undesirable reflections from a subject such as water, glass, or other objects with shiny surfaces. This filter also darkens blue sky.
Polarized Light
Light waves vibrating in one plane only as opposed to the multi-directional vibrations of normal rays. Natural effect produced by some reflecting surfaces, such as glass, water, polished wood, etc., but it can also be simulated by placing a special screen in front of the light source. The transmission of polarized light is restrained by using a screen at an angle to the plane of polarization.
Preset Iris
Diaphragm with two setting rings or one ring that can be moved to two positions. One is click-stopped, but does not affect the iris, the other moves freely and alters the aperture. The required aperture is preset on the first ring, and the iris closed down with the second just before exposure.
Prime Lens
A lens with a fixed focal length.
Program Exposure
An exposure mode on an automatic or autofocus camera which automatically sets both the aperture and the shutter speed for proper exposure. On some digital cameras it can set the ISO as well.
Programmed Auto
Camera sets both shutter speed and aperture for correct exposure and on some digital cameras it can set the ISO as well.
If you have any suggested additions or corrections to the Glossary, please contact us.
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