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AE

Auto Exposure, a function that allows the camera to set exposure automatically.

AE lock

Auto-Exposure lock: locking exposure at the value metered for one area of the frame. While exposure is locked, the photographer change the composition without changing exposure. This is helpful when the area used to set the exposure differs considerably in brightness from surrounding areas.

AF

AutoFocus, a function that allows the camera to focus automatically.

AF lock

AutoFocus lock: locking focus once it has been acquired by the camera – while focus is locked, one can change the composition without changing focus. This is helpful if the main subject will not be in a focus point in the final composition.

aperture

The opening in the lens through which light passes. Changing the size of this opening changes the amount of light passing through the lens.

aspect ratio

The width of an image relative to its height.

auto exposure

A function that allows the camera to set exposure automatically. Sometimes abbreviated as AE.

auto off delay

The delay before the monitor or camera turns off automatically; the delay before the exposure meters turn off automatically (auto meter-off).

autofocus

A function that allows the camera to set focus automatically. Sometimes abbreviated AF.

backlit

Of photographic subjects: positioned between a light source and the camera (i.e., positioned so that the light is coming from behind the subject). Pleasing results can be achieved by silhouetting the subject in a halo of light. It also provides separation between the subject and the background and can create a transparent effect with some subjects.

battery life

The number of pictures that can be taken with a fully-charged battery on a single charge.

capacity

The number of images that can be recorded to a memory card or other storage device. The number of images that can be recorded varies with image quality and size.

color cast

A tint evenly applied to an entire image.

composition

The arrangement of the subject and other objects in the frame.

compression

An algorithmic method of reducing file size.

contrast

By contrast we generally mean a difference in brightness. Increasing contrast increases the difference in density between light and dark areas of the image, while decreasing contrast decreases it.

contrast-detect autofocus

A type of autofocus that analyzes subject image data from the image sensor and chooses the lens position that produces the greatest contrast.

daylight sync (fill flash)

The use of a flash in daylight to illuminate (fill in) shadows in backlit subjects or shaded areas, reducing the contrast between brightly-lit and shaded areas of the frame for a natural effect.

depth of field (DOF)

The distance that appears to be in focus in front of and behind the point at which the lens is actually focused. DOF is thiny at large apertures (f1.2 – f2.8) and opposite at small appertures (f8 – f16). A shallow DOF isolates very well the subject from it’s background while a large DOF is necessary for landscapes.

diaphragm

A mechanism that controls the size of the lens aperture. Diaphragms are usually composed of overlapping blades or leaves that open or close to control aperture. Professional lenses from Nikon lineup uses 9 blades diaphragms, while the budget lenses are using only 7 blades.

EV

Exposure Value, a unit used to measure exposure. Higher values are appropriate for brighter lighting: the higher the value, the less light that falls on the image sensor. An EV of 1 corresponds to an aperture of f/1.4 at a shutter speed of 1 s.

exposure

The act of exposing the image sensor to light; the amount of light to which the sensor is exposed (sometimes stated as an exposure value).

exposure compensation

Modifying exposure from the optimal value selected by the camera, making photographs brighter or darker.

exposure indicator

The display showing the amount by which a photograph recorded at the current aperture and shutter speed will deviate from the optimal exposure selected by the camera.

exposure program

A graph showing the combinations of shutter speed and aperture that are automatically selected by the camera.

flash compensation

Adjusting the flash output from the value selected by the flash unit and camera. For example, flash output can be increased to light the subject more brightly, or decreased to make lighting less harsh.

flash control

A system for adjusting flash output based on the amount of light reflected from the subject.

flash-ready indicator

LED indicator that shows if a flash unit is charged and ready for use.

f-number

A unit used to measure the brightness of the image projected from the lens onto the image sensor.

focal length

The distance from the middle of a lens to the image sensor.

focus

The point where light rays converge; the act of adjusting an optical system so that the light from the subject converges at the focal plane. Subjects that are in focus are sharply detailed, while subjects that are out of focus appear blurred.

focus lock

Locking focus at the distance to a selected subject; while focus is locked, the photographer can change the composition without changing focus. This is helpful if the subject in question will not be in a focus point in the final composition.

focus point

An indicator showing a point in the frame that the camera can use for autofocus.

focusing screen

An element between the mirror and pentaprism or pentamirror in a single-lens reflex camera. The mirror reflects the image from the lens upward onto the screen. The areas of the image that are in focus are sharply defined on the screen, while the areas that are out of focus appear blurred. The photographer views the image passing through the screen in the viewfinder window.

front-curtain sync

A flash mode in which the flash fires as the shutter opens. Is the most common mode used in flash photography.

ghosting

A duplicate image of the sun or other bright light source at a different position in the frame from the original light source. Ghosting is distinct from flare, in which light from a bright light source is scattered or diffused over an area of the frame without creating a duplicate image.

guide number

A numeric expression of flash power. The higher the guide number, the greater the power of the flash and the greater the distance at which the flash can provide sufficient illumination for optimal exposure.

highlight

One of the brightest parts of an image.

histogram

A graph showing the distribution of pixels of different brightnesses in an image. The horizontal axis corresponds to brightness, the vertical axis to the number of pixels. If the image contains objects with a range of brightnesses, the distribution of tones in the graph will be relatively even. If the image is dark, the distribution will be shifted to the left, or to the right if the image is bright. Increasing exposure compensation shifts the distribution of tones to the right, while decreasing exposure compensation shifts the distribution to the left. Histograms can provide a rough idea of overall exposure when bright ambient lighting makes it difficult to see photographs in the monitor.

hue

The property that defines the difference between colors such as “red” and “yellow.” The hue adjustment available with digital cameras can be used to make reds more yellow or purple, yellows more green or red, greens more blue or yellow, blues more green or purple, and purples more blue or red.

image sensor

A device that converts light (i.e., images) into electronic signals. Image sensors are composed of micro-lenses for maximum light concentration, color filters that split light into separate color signals, photodiodes that convert light to electronic signals, transmission circuits that transmit these signals, and additional circuits that convert the signals to digital data.

image sharpening

A function that controls the sharpness of outlines in photographs.

image size

The dimensions of an image in pixels. Sometimes stated using abbreviations such as “L” (large), “M” (medium), or “S” (small).

ISO sensitivity

A measure of a digital camera’s responsiveness to light. Doubling this value doubles the camera’s sensitivity to light.

JPEG

An abbreviation of “Joint Photographic Experts Group,” an image data format that compresses images to reduce file size and allows more images to be stored. The amount of compression can be chosen from “fine” (compression ratio 1 : 4), “normal” (compression ratio 1 : 8), and “basic” (compression ratio 1 : 16). High compression ratios reduce file size, allowing more images to be stored, but also make the loss of image quality associated with compression more evident.

lens hood

An accessory that shades the lens to prevent light from the light source entering the lens directly and creating ghosting or flare.

live view

A system that displays the view through the lens “live” in the camera monitor, allowing photographs to be framed in the monitor.

long time-exposure

A photograph recorded by manually opening and closing the shutter for very slow shutter speeds. Two options are available for controlling the shutter: “bulb” and “time.” Long time-exposures are used to photograph night scenes or to create trails behind moving objects in pictures of fireworks, the night sky, or moving lights.

loss of detail in highlights

The loss of information in bright areas of the image due to overexposure. Details lost to overexposure are said to be “washed out” and appear as solid white.

loss of detail in shadows

The loss of information in dark areas of the image due to underexposure. Details lost to underexposure appear as solid black.

manual flash control

A type of flash control in which the flash intensity is selected manually.

manual focus (MF)

The act of focusing manually by rotating the lens focus ring until the subject is in clear focus. Used for close-ups of flowers, at night, and in situations in which autofocus may not produce the desired results. It is also characteristic to lenses that does not have AF: most older lenses were designed for MF.

metering sensor

A device that measures the brightness of the subject. The camera uses the data from a metering sensor to adjust shutter speed, aperture, and ISO sensitivity for optimal exposure.

MF

An abbreviation of “manual focus,” the act of focusing manually by rotating the lens focus ring until the subject is in clear focus. Used for close-ups of flowers, at night, and in situations in which autofocus may not produce the desired results.

minimum focus distance

The shortest distance at which an optical system can focus. In the case of digital SLR cameras, minimum focus distance is measured from the camera focal plane mark.

moiré

An interference pattern created when a repeating pattern in the subject is overlaid on the image sensor grid. In Nikon digital SLR cameras, moiré is greatly reduced by means of advanced image processing algorithms and optical low-pass filters.

NEF

This file extension for Nikon image files is an abbreviation of “Nikon Electronic Format”. RAW photographs taken with Nikon SLR cameras are stored in NEF format. Unlike JPEG and TIFF formats, in which repeated processing results in a progressive loss of image data and degradation of the image, NEF format stores the original image data separately from processing and retouch information, allowing images to be repeatedly processed and saved with no effect on the original image data.

noise

A type of image artifact (mottling or graininess) visible in photographs taken at high ISO sensitivities or slow shutter speeds.

optical viewfinder

The window in which the photographer frames the subject and checks focus. An electronic display such as a monitor can also be used as a viewfinder; in contrast to such electronic viewfinders, optical viewfinders consist of only of optical components such as lenses, prisms, and mirrors.

optimal exposure

The exposure that will produce a photograph with optimal brightness.

optional flash unit (Speedlight)

A flash unit that can be mounted on the camera accessory shoe. Optional flash units are generally more powerful than built-in flash units and have features adapted specifically to flash photography. Even if the camera is equipped with a built-in flash, optional flash units can provide lighting and features not supported by the built-in flash.

overexposure

Exposure greater than the optimal amount. Photographs that are overexposed are brighter than expected.

pentamirror

A mirror that reflects light from the viewfinder screen into the viewfinder eyepiece window.

pentaprism

A glass prism that refracts light from the viewfinder screen into the viewfinder eyepiece window.

peripheral illumination

The amount of light at the edges of an image. A “loss of peripheral illumination” is associated with the progressive darkening of an image from the center outwards.

perspective

A visual effect that causes objects to appear smaller as their distance from the viewer increases. If lenses with different focal lengths are used to photograph a subject at the same apparent size but at different distances from the camera, the apparent distance to the background will also change.

pixel count

The number of picture elements (pixels) in an image sensor.

portrait

A photograph with a human subject or human subjects.

RAW image

An image recorded using the 12- or 14-bit image data output from the image sensor. The original data from the image sensor are unmodified, allowing settings such as white balance, Picture Controls, and exposure compensation to be changed on a computer. Some cameras can create JPEG copies of RAW images using an option in the retouch menu.

rear-curtain sync

A flash mode in which the flash fires just before the shutter closes so that the trails of light produced by moving light sources naturally follow the motion of the source.

release mode

A setting that controls the shutter release. Release modes include single frame (a mode in which one photograph is taken each time the shutter-release button is pressed), continuous (the camera continues to take photographs as long as the shutter-release button is pressed), self-timer, and remote control modes.

reproduction ratio

The ratio of the size of the image on the image sensor to the actual size of the subject. For example, if the length of a 5 cm object on the film or image sensor is 1 cm, the reproduction ratio is 1 : 5 (0.2 ×).

saturation

A measure of the vividness of colors. Highly saturated colors are vivid, while colors with low saturation approach grey.

scene mode

A mode in which camera settings are adapted to a specific scene or type of subject.

self-timer

A mechanism that automatically releases the shutter after a fixed delay. The self-timer is used for shots that include the photographer, particularly group- and self-portraits.

shutter

A mechanism that controls the length of time that the image sensor is exposed to the light entering via the lens. The shutter is normally closed, preventing light from reaching the image sensor. When the shutter-release button is pressed all the way down, the mirror is raised and the shutter opens to allow light onto the image sensor.

slow sync

A flash mode in which the main subject is lit with the flash while slow shutter speeds are used to ensure that background objects beyond the range of the flash are correctly exposed.

subject blur (motion blur)

Blur caused by the subject moving while the shutter is open.

thumbnail

A small preview of an image. Digital cameras and computer programs often use thumbnails to list images.

TTL flash control

TTL is an abbreviation of “through the lens.” In TTL flash control, the camera meters the light passing through the photographic lens to determine flash level.

underexposure

Exposure less than the optimal amount. Photographs that are underexposed are darker than expected.

viewfinder

A small window in which the photographer frames the subject and checks focus.

vignetting

Loss of illumination at the periphery (usually in corners) of an image. The degree of loss depends on the subject and shooting conditions: in some cases, it may be more pronounced in some corners of the image than in others. Vignetting may be caused by a lens or lens hood blocking light from the flash and casting shadows on the subject, or when using a filter on the lens, especially at the lower focal distance.

VR lens

A lens incorporating Nikon’s unique vibration reduction technology. Two sensors in the lens sense pitching (front-back rotation) and yawing (left-right rotation) motions and adjust an internal set of lens elements to minimize blur.

zoom

The steady change in magnification. A zoom lens is a lens with an adjustable focal length, allowing you to shoot at different magnifications with a single lens.