An A to Z of Photography


Abbreviation for autoexposure. A good photograph requires the shutter speed and lens aperture to be set to expose the film with the proper amount of light. With AE, a camera makes these adjustments automatically.

Abbreviation for auto exposure bracketing. With this function, the camera automatically takes a rapid series of shots, slightly varying the exposure for each one. The photographer can then choose the best exposure. Especially useful with color reversal film.

Abbreviation for autofocus. It is usually activated with a half-press of the shutter, and is now available on almost all cameras except the most basic models.

Angle of view
The visual arc encompassed by a lens, usually measured on the diagonal of the frame. Angle of view is generally over 60? for wide-angle lenses, 40-60? for ?normal? lenses, and less than 40? for telephoto lenses. Examples in the 35mm format include 75? for a 28mm lens, 47? for a 50mm lens, 34? for a 70mm lens, and 24? for a 100mm lens.

Lens opening. The opening in a camera lens through which light passes to expose the film. The size of aperture can be either fixed or adjustable. Aperture size is usually calibrated in f numbers -- the larger the number, the smaller the lens opening. Aperture helps determine the depth of field of a lens: the larger the working aperture (i.e. the smaller the f number), the less of the photo will be in sharp focus.

Aperture-priority AE
An autoexposure mode that lets the user set the lens aperture. The camera then automatically determines the correct shutter speed. This allows effective control of depth of field, and is popular among advanced photographers.

APS camera
A camera that uses Advanced Photo System film, a small film format designed for ease of use. The drop-in cartridge makes film loading especially simple. A magnetic strip on the film records shooting information to assist in processing and printing.


Back focus
A situation where the lens is actually focused behind the main subject, resulting in a slight softness of that subject. Back focus is a common problem when there is another object behind the main subject and the auto focus locks onto it instead.

The backdrop behind the main subject, and a key element of photographic composition. Choosing the right background ? a particular color, for example, or buildings or trees or sky ? has a major effect on the impact of your photo.

Light, particularly sunlight, that illuminates subject on the side opposite the camera. It can fool a camera into underexposing the subject, i.e. making it too dark. Backlight can be countered by increasing the exposure, and can produce very attractive portraits.

Backlight compensation
Increasing exposure to counter backlight on a subject. Because most metering systems tend to underexpose a backlit subject, it?s generally a good idea to increase exposure by about 1.5EV.

Stands for binary digit. It is the basic unit of digital information.

The BMP format is compatible with most graphic software for Windows PCs. Images can be saved either in full color (16.77 million colors) or in 256-color formats. However, as data is not compressed, BMP image files are very large.

Bulb (B)
A setting that lets you open and close the shutter manually, useful for very long exposures (e.g. 5 or 10 seconds or more). Traditionally it was activated by a cable release with a lock on it. Most current cameras use an electronic control cable instead.

A unit of measure equal to 8 bits of digital information. The standard unit of measurement for file size.


Camera angle
The relationship of the position of the camera to that of the subject. Most common is to hold the camera horizontal to the subject, but often more impact can be achieved by altering the camera angle to change the perspective and line the subject up with an interesting background.

Camera batteries
Batteries designed to power the various functions of cameras. Lithium batteries are popular for this use thanks to their small size and long life. Common 3V types include CR2 and CR123A, while 6V types include CRP2 and 2CR5. Flash units normally use AA-size batteries.

Camera shake
Any movement of the camera at the moment the shutter is pressed. Camera shake is one of the main reasons for blurry photos, and is especially likely at shutter speeds of 1/30 second or below. Another cause is pressing the shutter with too much force.

The container housing the roll of film, especially for 35mm film. 35mm film loaded into a cassette is also called 135 format. It is available in lengths of 12, 24, and 36 frames, and can be used in any 35mm camera past or present.

Bright reflections of light seen in the eyes of a photographed subject. Catchlights are especially important in head-and-shoulder portraits and large prints, where they give sparkle and life to a subject?s eyes. They are easily achieved with a flash or reflector in front of the subject.

Charge Coupled Device: one of the two main types of computer chips used to capture digital camera images.

A photo taken close to the subject, usually defined as within 1m or less. Popular close-up subjects include flowers, insects, and small objects. While most ordinary lenses can focus as close as 40-50cm, specialized macro lenses offer higher performance for serious close-up photography.

Close-up frame marks
Small additional marks inside the viewfinder of compact cameras that approximate the frame size when shooting at close distances. Use these marks when shooting close-up to prevent mistakes like cutting off the heads of your subjects.

Complementary Metal-Oxide Semiconductor: one of the two main types of computer chips used to capture digital camera images. CMOS sensors are currently found in only a handful of digital cameras.

Color negative
Film for color prints. The film records a negative image (i.e., colors and lightness/darkness exactly opposite of reality), which then becomes positive when printed onto color paper. Color negative film is tolerant to a wide range of exposure, making it easy to use.

Color reproduction
The color fidelity and beauty with which color prints and slides render the original scene. Different films have different color characteristics, and are each capable of producing their own distinctive ?look?.

Color reversal film
Film for color slides. The film records a positive image (i.e. colors and lightness/darkness the same as reality). This type of film can be used not only for slides but also direct color prints and scanning. Exposure must be fairly precise, so color reversal film is best suited to intermediate to advanced photographers.

Color slide
A frame of color reversal film placed in a film mount, for use in a slide projector. The sharpness and vibrant colors of this type of film give slide presentations their impact and enjoyment.

Color temperature
A measure of the redness (warmth) or blueness (coolness) of light, expressed in degrees Kelvin. Higher numbers mean cooler light and lower numbers indicate warmer. Standard noon daylight is considered to be 5400K, while the light two hours after sunrise or before sunset is 4800K.

Compact camera
The general term for small, light cameras designed for convenience. While they do not offer interchangeable lenses, they are perfectly usable for snapshots, and some do employ high-performance optics. Ideal for travel or ?visual notebook? applications.

The arrangement of all the visual elements within a photo. Note that the main subject does not always have to be in the center of the frame. When composing a shot, consider the whole frame, all the way to each corner.

Continuous shooting
Holding down the shutter to take one shot immediately after another. Cameras generally can shoot one to two frames per second, while higher speed models can achieve four to five frames. Continuous shooting is especially useful in sports photography.

The difference in light level between the brightest parts of the image (the highlights) and the darkest ones (the shadows). High-contrast images show a stark difference between light and dark, while low-contrast ones are more muted.

Correct exposure
A combination of shutter speed and lens aperture that delivers exactly the right amount of light to produce a good image on film. The camera function that automatically makes these settings is known as autoexposure (AE).


Data imprinting
Data printed by camera on the film next to or over images. Types of imprinted data can include date and time, shooting mode, focus distance, aperture and shutter speed, exposure compensation, AF/MF, flash on/off etc. A number of 645 and APS cameras offer this capability, and data backs are also available for some camera models.

The quality of three-dimensional depth in a photograph. There are a number of ways to achieve a sense of depth, such as compressing the perspective of a distant subject, dramatic cameras angles, and selective focus.

Depth of field
The distance in front of and behind the point of sharpest focus that is still acceptably sharp. The larger the aperture of a lens, the less depth of field, while wide-angle lenses offer greater apparent depth of field.

Direct print
A print made directly from a color slide. Fujifilm direct prints are called Fujichrome prints, in contrast to Fujicolor prints, which are made from color negative film. Direct prints tend to look sharp with high-contrast and deep, rich colors.

DX code
A camera-readable code printed on the outside of 35mm film cassettes and APS cartridges. It provides information on ISO speed and film type and length, allowing the camera to adjust exposure settings and frame count.


Abbreviation for exposure index, a figure used when film is ?rated? (exposed) at a speed other than its nominal ISO speed. An ISO 100-speed film for example can be pushed to an EI of 400 by exposing it as if it were an ISO 400 film, and then processed accordingly.

Refers to larger print sizes, usually 8 x 10? and above. Enlargements offer greater impact than ordinary size prints.

Exposure value, a measure of how much light strikes the film. Exposure is determined by the combination of shutter speed and lens aperture. Each doubling/halving of shutter speed or opening/closing of the lens by one f-stop is equivalent to 1 EV.

Exposure compensation
A manual override that allows you to increase or decrease exposure when you have reason to believe that the camera?s autofocus will not produce a correct exposure. Cameras typically offer a range of ?3EV of exposure compensation. Normal compensation for backlight, for example, is +1.5EV.


Fast lens
A lens with a wide maximum aperture (e.g. f/1.7 or f/2.8), allowing in a large amount of light. While they perform well in low light, fast lenses tend to be large and expensive. Lenses with small maximum apertures (e.g. f/5.6 or f/8) are called slow lenses.

Supplementary light from a flash, lamp, or reflector, used to brighten the shadows that occur on a subject illuminated by direct sunlight. Shooting without fill in this situation tends to produce harsh contrast.

An optical device that attaches to the front of a lens to provide a specific visual effect. Common types include UV filters to block ultraviolet light, polarizing (PL) filters to cut reflections and darken skies, light-balancing (LB) filters to compensate for dawn and dusk and overcast light, and color correction (CC) filters for precise color control.

Flash photography
Using a built-in or external flash to illuminate your subject. Skillful use of a flash can brighten a subject for beautiful results, but is best used together with existing light for a natural-looking photo.

F number
A measure of the aperture, i.e. optical diameter, of a lens, written either ?f/? (e.g. f/2.8) or with a colon (1:2.8). The smaller the number, the brighter the lens. The progression of f- numbers is: f/1.0, f/1.4, f/2.0, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f32.

Adjusting the point of maximum sharpness when photographing a subject. Autofocus cameras handle this automatically, but note that when shooting close up, it is often quicker and more accurate to switch to manual focus.

Focus lock
A feature on most AF cameras that allows you to focus on one part of the image by half-pressing and holding the shutter button, then recomposing and further pressing the shutter to take the shot. Routine use of the focus lock helps ensure that your focus is exactly where you want it.

The portion of a scene closest to the camera, in contrast to the middle ground and background. Including a foreground in a landscape or snapshot helps create a sense of depth, and can add a useful accent or setting for the main, more distant subject.

Frame size
The area of the film that records the actual image. Also known as film format. Common formats include APS (16.7 x 30.2mm), 35mm (24 x 36mm), 645 (41.5 x 56mm), 6x7 (56 x 69mm), 6x8 (56 x 76mm), and 6x9 (56 x 82.6mm).

Front focus
The situation when the lens is actually focused in front of the main subject, resulting in a slight softness of that subject. Front focus can be problem when photographing a distant landscape or scene and the autofocus instead locks onto an object in the foreground.

Front light
Light striking the subject from the same direction as the camera. This even, direct illumination makes it safe to use auto exposure. While front light is ideal for shots of large groups of people, the lack of shadows and contours does not make this the most attractive light for most subjects.

Full aperture
To use a lens with its aperture fully open, i.e. at its largest setting. Full aperture for an f/2.8 lens is thus f/2.8. This minimizes the zone of sharpness (technically known as depth of field), helping to soften backgrounds and make your subject stand out.



The standard print format from negatives from APS film. Its 16:9 aspect ratio is the same as high-definition TV, and is useful for showing the horizontal or vertical expanse of a subject, as well as adding a sense of depth to the scene.

The lightest parts of an image. Highlights are the opposite of shadows, the darkest parts of the image, and it is the transitions between the two that give photos their sense of tonality. A correct exposure should make highlights sparkle while still preserving their details.

High shutter speed
Shutter speeds of roughly 1/250 second or faster. Speeds of 1/250 and 1/500 are generally fast enough to prevent camera shake. Modern cameras offer ultra-high shutter speeds of 1/1000, 1/2000, and even 1/4000 and beyond.

High-speed film
Film with a speed of ISO 400 to 800. Modern high-speed films offer very fine grain and rich color, making them a good all-purpose replacement for the slower ISO 100 films of the past.

A frame oriented with the long side on the horizontal, usually when the camera is kept level with the horizon for a natural-looking shot. While most photos are horizontal, more advanced photographers tend seek out variety by increasingly shooting vertical as well.


Image quality
An evaluation of the overall visual quality of a finished print. Image quality criteria include good sharpness, smooth tonality, fine grain, shadow and highlight detail, and color fidelity and richness.

ISO speed
An international standard measurement of film sensitivity. A more sensitive film (i.e., one that requires less light for an exposure) is called ?high-speed?, while a less sensitive one is ?low-speed?.


JPEG compresses files by discarding color information that the human eye cannot perceive. This format significantly reduces the file size, but image quality deteriorates as the compression rate increases. Once the data is saved, the compression cannot be reversed.



The range of allowable exposure values of a film. While there is usually a single ?correct? exposure that yields the full range of tonality from shadows to highlights, film does tolerate some degree of over- or under-exposure, and this can be taken into account when setting exposure.

Liquid Crystal Display screen found on many digital cameras that allows previewing or reviewing of images.

LCD panel
A display panel found on most cameras that can provide shooting information including film loading status, frame number, date and time, flash on/off, battery status, shutter speed, aperture, scene mode, metering mode, infinity focus, etc.

Lens hood
A circular shade that blocks extraneous light from entering a lens. Using a lens without a hood risks flare, which often appears as a white haze over the image.

Low-speed film
Film with a sensitivity below ISO 100. These films feature extremely fine grain, excellent sharpness, and rich, vivid color reproduction. Their slow speed tends to result in slow shutter speeds, making advisable a tripod or other camera support.


Macro lens
A lens designed for close-up photography, i.e. within about 20cm. Macro lenses are the preferred choice for photos of flowers and insects. Popular focal lengths are 50-60mm, while 90-100mm macro lenses are useful when you need slightly more distance to your subject.

Any non-automatic function. Common manual settings include manual focusing, manual control of exposure (by setting both shutter speed and aperture), and manual inputting of film ISO, overriding the DX code.

A unit of measure of stored data equal to 1,024 Kilobytes, or 1,048,576 bytes.

Indicates image resolution of one million pixels or more. The more pixels in an image, the higher the resolution and therefore the greater the quality of the image.


Nature photo
Any photo of a natural subject, from animals, birds, and insects to plants and flowers and even underwater subjects. There exist an infinite number of possibilities, using all lenses from telephoto to macro. Especially popular and easy to photograph close-up are flowers and birds.

Graininess in an image, caused by too little light or by defects in the electrical signal generated during the image-capture process.


Out of focus
Falling outside the zone of sharp focus of a lens. Common examples include the blurred grass in the foreground when focusing on a distant landscape, or the blurred background in a close-up shot of a flower.

When the film has received too much light for a correct exposure. Negatives look dark, producing a white haze and burned-out highlights on prints. Overexposed slides are pale and hazy.


Pan focus
To focus a lens so that everything from near to far is in acceptably sharp focus. This is best done by using a wide-angle lens and changing down to a small aperture, then setting focus to maximize the area of the frame that appears sharp.

Following a moving subject with the camera, usually using a slow shutter speed of about 1/60 second. This has the effect of blurring the background while keeping the subject in sharp focus, bringing out a sense of movement and speed.

Viewfinder inaccuracy due to the viewfinder and lens seeing the subject from slightly different angles. Parallax increases as you move closer to the subject. One of the benefits of the SLR camera design is the absence of parallax.

Stands for picture element. A single dot on a computer display or in a digital image.

A photo of a person, normally posed. In the 35mm format, a lens in the 80-100mm range gives a natural perspective. Rather than shooting head-and-shoulder portraits straight on, photographers usually have the subject sit at an angle, and then turn their head toward the camera. Serious portrait work is best done with a large-format camera.

Program AE (P)
A fully automatic AE mode in which the camera determines both the shutter speed and the aperture. The program is designed to minimize camera shake while allowing for as much of the scene to be in focus as possible.


R .

The RAW image format contains data as it comes directly off a digital camera's image sensing device, with no in-camera processing performed.

Red-eye reduction
A mode on many cameras that fires a pre-exposure light or flash in order dilate subjects? pupils and prevent the common problem of red-eye with flash photography. Especially useful when photographing people in low light.

A white, silver, or other reflective object used to reflect light into the shadow areas of a subject, especially in direct sunlight where contrast is high. Reflectors can be bought or easily improvised, and are especially essential at model shoots.

The number of pixels per linear inch in an image, or the number of dots per linear inch produced by an output device.


Sense of motion
A quality of photographs of moving objects where the camera has not simply frozen the motion, but shows it in some way. This can be done by purposely letting the subject blur somewhat, or by using a slow shutter and panning with the subject, blurring the background.

To expose film at a higher EI than its nominal ISO, and then compensate in the processing stage.

The darkest parts of a subject or image. The opposite of shadows are highlights, the lightest parts of the image, and it is the transitions between the two that give photos their sense of tonality. A correct exposure should preserve fine detail even in shadow areas.

Slide mount
A plastic or stiff paper frame used to hold a frame of slide film. 35mm slide mounts measure 5 x 5cm. Usually ordered when delivering film to the lab by asking for the processed film to be ?mounted?.

Slow shutter
A slow shutter speed, i.e. the shutter remains open for a long time. Generally this means 1/30 second or longer. As handholding a camera at slow shutter speeds often results in camera shake, always try to use a tripod or other support to steady the camera.

Abbreviation for single-lens reflex, a type of camera that shows the user the actual view through any lens that is attached, from wide-angle to telephoto to zoom. Its versatility makes it indispensable for serious photography.

A photograph taken quickly and reflexively, usually of people: ordinary activities in city streets or the countryside, children at play, etc. A compact camera with high-speed film and a wide-angle lens is the customary tool for this kind of photography, but telephoto lenses can also be used. The key is to approach the subject as closely as possible.

Solution leakage
Liquid leakage that can result from leaving a discharged battery in a camera. Damage caused to internal components can cause malfunctions and can be difficult to repair. Always switch cameras off when not in use. For longer storage, remove batteries and keep in a cool, dry place.

A film?s sensitivity to light, i.e. how much light is required to produce an image. The more sensitive the film, the faster it is said to be. Film speed is expressed in ISO, e.g. ISO 400 or ISO 800, with higher numbers indicating greater speed.

Spot metering
A metering mode found in many SLR cameras that judges exposure according to a small area in the center of the frame. Spot metering is useful for subjects with high-contrast, allowing you to meter both light and dark areas and then choose an intermediate exposure. Another use is for stage photography or other situations where subjects are lit selectively.

The most important object in a photograph ? a person, an animal, a plant, a mountain etc. While the subject should be the focus of the photograph, other objects can be included to add accent and interest. It?s always worth asking yourself: what is my subject in this photo, and how am I trying to portray it?


The TIFF format was developed to permit handling of image data on different platforms. It allows image files to be saved with no compression.

The gradations of light and dark of a subject or photo, from highlights to shadows. Tonality can be hard, with a strong difference between tones, or soft, meaning a more gentle transition of tones.

An essential accessory for holding a camera steady at slow shutter speeds or when using long lenses. A tripod is the best way to prevent camera shake. When choosing a tripod, look for one with simple operation and of the largest size practical for your needs.


When the film has not received enough light for a correct exposure. Underexposure makes negatives look ?thin? (light), which produces murky, grainy prints. Underexposed slides look dark and muddy.

Use-by date
The date by which film should be exposed and processed, usually printed on the outside of the box. Using film by this date assures full image quality. Avoid using out-of-date film, as it can result in loss of image brilliance and detail.


A frame oriented with the long side on the vertical. Holding the camera vertically and including foreground, middle ground, and background is an effective way to create a sense of depth. Good vertical compositions are a mark of an accomplished photographer.

The window on a camera that shows your scene. Autofocus cameras normally focus on the center of the frame as shown in the viewfinder. Use focus lock to ensure that you?re focused correctly: center the frame over your subject, half press the shutter and hold it, then recompose to your liking and press the shutter the rest of the way.


White balance
Adjusting the camera to compensate for the type of light illuminating the photographic subject. Eliminates unwanted color casts produced by some light sources, such as fluorescent lighting.




Zoom lens
A lens that offers a continuous range of focal lengths, especially from wide-angle to telephoto. While larger, heavier, and slower than comparable single focal-length lenses, zooms offer convenience and increasingly good quality, and have gained a large following among photographers.

Zoom up
To use a zoom lens to enlarge one part of a subject and crop out the rest. Because the aperture of most zooms becomes smaller at longer focal lengths, be careful when zooming up to ensure that your shutter speed remains high enough to prevent camera shake.


135-format film
The familiar 35mm film, contained in a cassette. The most popular film size, it is available in 12-, 24- and 36-exposure rolls. A DX code on the cassette allows the camera to set ISO speed and other parameters automatically.

35mm camera
A camera that uses 35mm film, a format that allows them to be small and convenient. While they take a variety of forms, they can generally be divided into SLRs, which feature interchangeable lenses, and compact cameras, with fixed lenses.