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A

Denotes the degree of refraction of light of different wavelengths to different extents, given by a transparent material, such as glass. The lower the Abbe number, the greater the dispersion of colors.

Auto Backlighting Control, metering feature that automatically recognises a subject in back lighting condition and increase the exposure to compensate.

Failing in the ability of a lens to produce a true image. There are many forms of aberration and the lens designer can often correct some only by allowing others to remain. Generally, the more expensive the lens, the less its aberrations (More attention to optical quality). While no single lens is called a 'perfect lens'. The "ideal" lense would reproduce a subject in a faithful, clearly defined image on film. Aberrations, which can be divided into six basic faults, affect the Ideal performance in an optical system.

1. Spherical aberration. Basically, a beam of light passing through a lens parallel to the optical axis converges to form 3 focused image on the film. Spherical aberration is the term for an optical fault caused by the spherical form of a lense that produces different focus points along the axis for central and marginal rays.
2. Curvature of field. This optical defect causes points on an object plane perpendicular to the lens axis to focus on a curved surface rather than a plane.
3. Astigmatism. Rays of light from a single point of an object which is not on the axis of a lense fail to meet in a single focus thus causing the image of a point to be drawn out into two sharp lines, one radial to the optical axis and another perpendicular to this line, in two different planes near the curvature of field.
4. Coma. This optical defect causes the image of an off-axis point of light to appear as a comet-shaped blur of light. Coma, as well as curvature of field and astigmatism, degenerate the image forming ability of the lense at the rims of the picture.
5. Distortion. Even if the first four aberrations were totally eliminated, images could result that still have a distorted appearance. For an example, an rectangle may appear as a barrel or pin cushion-shaped object.
6. Chromatic aberration. This aberration is caused by light rays of different wavelengths coming to focus at different distances from the lense. Blue will focus at the shortest distance and red at the greatest distance. Since the natural rays of light are a mixture of colors, each aberration will give a different value corresponding to each color thus producing blurred images.

Light which is not reflected or scattered by a light-opaque substance is absorbed by the material and mostly turns into heat.

Also often called "Hot Shoe". The early flash types were simple metal brackets. To install a flash unit, you just slide the mounting foot of the flash into the accessory shoe. No electrical connection is made between camera and flash - it's just a simple and convenient way to attach the flash unit to the camera. Subsequent accessory shoes have been built as part of the camera and usually reat on top of the camera's pentaprism; others are separate items that you mount on the camera body when you need them. Some like the Nikon early professional camera has special dedicated which was designed around the rewind knob.

Cameras with active autofocus systems determine the correct focussing distance by projecting beams of energy - usually infrared or light energy - out to the subject.

The available light surrounding a subject. Light already existing in an indoor or outdoor setting that is not caused by any illumination supplied by the photographer.

The area of a scene that a lens covers or sees. Angle of view is determined by the focal length of the lens. A wide-angle lens (short-focal-length) includes more of the scene-a wider angle of view-than a normal (normal-focal-length) or telephoto (long-focal-length) lens. It can also be explained as the extent of the view taken in by a lens. For any particular film size, it varies with the focal length of the lens. Usually expressed on the diagonal of the image area. Basically, there are three types of angles which can be measured (based on horizontal, vertical and diagonals of the film frame), the lense must be designed to cover the widest angle in the diagonal direction. Thus, the angle of view is the angle between imaginary lines drawn from the opposite ends of the film plane to the second nodal point of the lense. All objects within this angle will be recorded by the lense on the film.

A small, circular opening inside the lens that can change in diameter to control the amount of light reaching the camera's sensor as a picture is taken. The aperture diameter is expressed in f-stops; the lower the number, the larger the aperture. For instance, the aperture opening when set to f/2.8 is larger than at f/8. The aperture and shutter speed together control the total amount of light reaching the sensor. A larger aperture passes more light through to the sensor. Many cameras have an aperture priority mode that allows you to adjust the aperture to your own liking.

Light from a man-made source, usually restricted to studio photo lamp and domestic lighting. When used to describe film (also known as Type A or Type B) invariably means these types of lighting.

The ratio of width to height in photographic prints - 2:3 in 35 mm pictures to produce photographs most commonly measuring 3.5 x 5 inches or 4 x 6 inches; Advanced Photo System cameras deliver three aspect ratios as selected by the user.

A lens whose curved surface does not conform to the shape of a sphere; lenses are usually ground or molded with spherical surfaces; because a spherical surface lens has difficulty in correcting distortion in ultra-wideangle lenses or coma in large-aperture lenses brought about by spherical aberration, an aspherical lens is used.

This means the camera supports the electrical interface standard, defined by the PC Card Association (formerly PCMCIA), known as ATA (AT Attachment). This is the mobile computing equivalent of the IDE standard for desktop computers. Most computers have ATA support built-in. ATA is supported by most operating systems like Microsoft Windows 3.1, Windows '95, Windows CE, IBM OS/2, Apple System 7, etc. ATA is supported by most computer manufacturers including IBM, Compaq, Packard Bell, Dell, Gateway 2000, etc.

Auto exposure bracketing performs automatic exposure bracketing with varied shutter speed and/or aperture.

Device used in certain cameras, projectors and enlargers that focuses the image automatically.

A supplementary lighting system used to help passive autofocussing systems achieve focus in low-light conditions.

The point on the image which the camera uses to determine correct focus, usually marked in the viewfinder somehow - a circle, a square, brackets, etc.

System of exposure setting in a camera, in which the electric current produced or inhibited by the action of light on a photoelectric cell operates a mechanism that adjusts the aperture and/or the shutter speed automatically.

A common feature on many SLRs with automatic exposure which allows you to lock in the current exposure settings for a period of time, regardless of what happens to the incoming light levels in the viewfinder.

A self-contained flash unit which determines correct flash metering itself - flash metering is handled neither by the camera nor directly by the photographer.

Lens diaphragm which is controlled by a mechanism in the camera body coupled to the shutter release. The diaphragm closes to any preset value before the shutter opens and returns to the fully open position when the shutter closes.

B

A shutter-speed setting on an adjustable camera that allows for time exposures. When set on B, the shutter will stay open as long as the shutter release button remains depressed. Another similar option is the "T" setting, where it never drains the battery power on automatic camera body.

The part of the scene the appears behind the principal subject of the picture. The sharpness of the background can be influenced by apertures and shuttle set. In the flash mode, bulb setting usually is set for absorbing more ambience light (background information), so the end result of the exposure won't be pitch dark.

Distance between the back surface of the lens and the image plane, when the lens is focused at infinity.

Any light coming from behind the subject.

Information printed on the back of a picture by the photofinisher. The system standard requires the printing of frame number, film cassette number and processing date automatically on the back of each Advanced Photo System print; may also include more detailed information, such as customized titles and time and date of picture-taking.

Placement of colors, light and dark masses, or large and small objects in a picture to create harmony and equilibrium. Description applied to colour films to indicate their ability to produce acceptable colour response in various types of lighting. The films normally available are balanced for daylight (550~6000K photo lamps (3400K) or studio lamps (3200K).

A type of TTL auto flash operation which uses the camera's exposure meter to control ambient light exposure settings, integrated with flash exposure control. That is, flash output level is automatically compensated to balance with ambient light, resulting in a better exposure for both subject and background.

A flash photography technique that balances flash illumination with the scene's ambient light. This automatic operation utilizes the some camera's Automatic Balanced Fill Flash System with TTL Multi Sensor and a compatible dedicated TTL Speedlight.

The folding (accordion) portion in some cameras that connects the lens to the camera body. Also a camera accessory that, when inserted between lens and camera body, extends the lens-to-film distance for close focusing or macro phtography. Some retains the automatic functions where some have to stopdown the lens for manual exposure reading.

A shutter whose blades operate between two elements of the lens. Most medium format cameras like the Hasselblad have one family of lens with shuttle and another without. Most lenses in this family have a smaller maximum aperture than the other family.

Light that is directed away from the subject toward a reflective surface.

Often called handle mount flash. It comprised of one arm of the L-shaped bracket extends under the camera body and uses the camera's tripod socket to mount the camera on the bracket. The vertical arm of the bracket serves as a handle and mounts a flash unit in an accessory shoe often on top of the handle portion, but there are other methods. Flash mounted in a bracket usually requires a separate electrical cord to make the electrical connection between camera body and flash unit.

Taking a series of photographs of the same subject at different exposures to insure the "correct" exposure; useful when shooting in situations where a normal metering reading is difficult to obtain. Taking additional pictures of the subject through a range of exposures-both lighter and darker-when unsure of the correct exposure.Some top cameras have provision for automatic bracketing, while manually you can bracket by the use of, say, adjust apertures or shuttle speeds setting or both, manually influent the ASA setting or even adjust the flash output power etc...

Flashbulbs - A special flashbulb that can be used at certain shutter speeds is called "FP" where the initials stand for Focal Plane. Designed for use with focal-plane shutters these bulbs make a nearly uniform amount of light for a relatively long time. The idea is to turn on the light before the focal-plane shutter starts to open and keep the light on until the shutter is completely closed. Firing delay for flashbulbs is indicated by code letters: "F"- fast; "M"- medium; "MF" - mediurn fast; "S" - slow.

Basically, a darkroom process that gives additional exposure to part of the image projected on an enlarger easel to make that area of the print darker. This is accomplished after the basic exposure by extending the exposure time to allow additional image-forming light to strike the areas in the print you want to darken while holding back the image-forming light from the rest of the image. Sometimes called printing-in.

Lighting in which the main source of light is -placed high and directly in front of the subject.

C

"Classic" format - one of the three selectable Advanced Photo System print formats; identical to the 2:3 aspect ratio used in 35 mm photography and suitable for most general-purpose shots.

Various positions of the camera (high, medium, or low; and left, right, or straight on) with respect to the subject, each giving a different viewpoint, perspective or visual effect.

Movement of camera caused by unsteady hold or support, vibration, etc., leading, particularly at slower shutter speeds, to a blurred image on the film. It is a major cause of un-sharp pictures, especially with long focus lenses.

Extra shutter used in some medium format cameras or in conjunction with a group of extreme high speed shutters.

Reflection of a light source in the subjects eyes.

Electronic sensor used by all autofocus cameras, capable of detecting subject contrast; also an image-receiving device for video camera.

Abbreviation for color compensating filter.CC filters are designed primarily for introducing or correcting color bias at the camera exposure stage.

Technique pioneered by Eadweard Muybridge, for recording objects in motion by taking photographs at regular intervals.

A picture taken with the subject close to the camera-usually less than two or three feet away, but it can be as close as a few inches.

A lens attachment placed in front of a camera lens to permit taking pictures at a closer distance than the camera lens alone will allow.

In general, lenses are designed for maximum performance at infinity. Accordingly, when the lense barrel is fully extended to the shortest focusing distance, resolution is reduced. Although this is negligible for ordinary lenses, it becomes increasingly important in lense specially designed for close distance photography. Lense designers adopted a system where mechanism moves certain lense components as a unit automatically correcting for aberrations. This assures high lense performance throughout the focusing range.

A lens covered with a very thin layer of transparent material that reduces the amount of light reflected by the surface of the lens. A coated lens is faster (transmits more light) than an uncoated lens.

Colors at the blue end of the spectrum that suggest a cool atmosphere.

Composition employing various different materials combined with original artwork attached to some type of backing.

How a color film reproduces the colors of a scene. Color films are made to be exposed by light of a certain color quality such as daylight or tungsten. Color balance also refers to the reproduction of colors in color prints, which can be altered during the printing process.

Pale colored filters used to warm or cool subject colors.

Film designed to produce color image with both tones and colors reversed for subsequent printing to a positive image, usually on paper.

Film designed to produce a normal color positive image on the film exposed in the camera for subsequent viewing by transmitted light or projection on to a screen.

Purity or strength of color, due to the absence of black, white or gray.

Response of a sensitive material to colors of different wavelengths.

Description of the color of a light-source by comparing it with the color of light emitted by a (theoretical) perfect radiator at a particular temperature expressed in kelvins (K). Thus "photographic daylight" has a color temperature of about 5500K. Photographic tungsten lights have color temperatures of either 3400K or 3200K depending on their construction.

Part of a compound lens consisting of one element (single lens) or more than one element cemented or otherwise joined together. A lens may therefore be described as 4-element, 3-component when two of the elements are cemented together.

The pleasing arrangement of the elements within a scene-the main subject, the foreground and background, and supporting subjects.

Generally a simple lens used to collect light and concentrate it on a particular area, as in enlarger or projector. Frequently in the form of two planoconvex lenses in a metal housing. A condenser, normally of the fresnel type, is used to ensure even illumination of the viewing screens on SLR cameras.

An enlarger with a sharp, undiffused light that produces high contrast and high definition in a print. Scratches and blemishes in the negative are emphasised.

The range of difference in the light to dark areas of a negative, print, or slide (also called density); the brightness range of a subject or the scene lighting. It may be also explained as tonal difference. More often used to compare original and reproduction. A negative may be said to be contrasty if it shows fewer, more widely spaced tones than in the original.

Or another way to explain, a difference in visual brilliance between one part of the image and another; without contrast, there would be no such thing as a visible image; a line in a photograph is visible only because it is either darker or lighter in tone than the background; every distinguishable part of the image is the result of a contrast in tonal values.

Numbers (usually 1-5) and names (soft, medium, hard, extra-hard, and ultra hard) of the contrast grades of photographic papers, to enable you to get good prints from negatives of different contrasts. Use a low-numbered or soft contrast paper with a high contrast negative to get a print that most closely resembles the original scene. Use a high-numbered or an extra-hard paper with a low-contrast negative to get a normal contrast paper.

Higher-than-normal contrast including very bright and dark areas. The range of density in a negative or print is higher than it was in the original scene.

Setting at which a lens gives its best performance. The setting offers the best compromise between diffracting due to small aperture and lens aberrations apparent at wide apertures.

Printing only part of the image that is in the negative or slide, usually for a more pleasing composition, in medium format, esp the 6 x 6, some form of cropping is necessary for publishing on A4 magazine format. May also refer to the framing of the scene in the viewfinder.

D

A fully automatic flash that works only with specific cameras. Dedicated flash units automatically set the proper flash sync speed and lens aperture, and electronic sensors within the camera automatically control exposure by regulating the amount of light from the flash. A simple glance can differentiate by identifying the multiple contacts on the hot shoe (the place where the flash is mounted).

Mechanism delaying the opening of the shutter for some seconds after the release has been operated. Also known as self-timer.

The zone of acceptable sharpness in front of and behind the subject on which the lens is focused; extends approx. one-third in front of and two thirds behind the in-focus subject; dependent on three factors: aperture, focal length, and focused distance; the wider the aperture, the longer the focal length, and the closer the focused distance, the less the depth of field, and vice versa; in comparison to a normal lens, wideangle lenses have inherently more depth of field at each f-number and telephoto lenses have less.

Since this element is very important, another simpler way to explain is the amount of distance between the nearest and farthest objects that appear in acceptably sharp focus in a photograph. Depth of field depends on the lens opening, the focal length of the lens, and the distance from the lens to the subject or can explain as in simpler term as the zone of sharpest focus in front of, behind, and around the subject on which the lens is focused; can be previewed in the camera - very handy for critical work.

The distance range over which the film could be shifted at the film plane inside the camera and still have the subject appear in sharp focus; often misused to mean depth of field.

An adjustable device inside the lens which is similar to the iris in the human eye; comprised of six or seven overlapping metal blades; continuously adjustable from "wide open" to "stopped down"; controls the amount of light allowed to pass through the lens and expose the film when a picture is taken; a]so controls the amount of depth of field the photograph will have; in lenses designed for single-lens reflex cameras, there are basically two types of diaphragms: Lens opening. A perforated plate or adjustable opening mounted behind or between the elements of a lens used to control the amount of light that reaches the film. Openings are usually calibrated in f-numbers. The more blades used will have a more natural and rounded spots.

There are two types of diaphragms:

Automatic: The most popular type; controlled by a single aperture ring; during viewing and focusing, the diaphragm remains wide open, allowing the maximum amount of light to go to the viewfinder for a bright and easy-to-focus image; at the instant of exposure, it stops down automatically to a particular aperture and then reopens to full aperture immediately afterward.

Manual Preset: Used in some specific lenses; controlled by two separate rings; the preset ring is first set to the desired aperture, then the aperture ring is rotated to stop down the diaphragm manually for metering or prior to taking pictures.

Displaying two colors - one by transmitted and one by reflected light.

Setting the camera controls to produce minimum depth of field, so that image sharpness is limited to a particular subject element.

Light rays scattered and change direction when they are passed through a small hole or close to an opaque surface.

Lighting that is low or moderate in contrast, such as on an overcast day.

Softening detail in a print with a diffusion disk or other material that scatters light.

An enlarger that combines diffuse light with a condenser system, producing more contrast and sharper detail than a diffusion enlarger but less contrast and blemish emphasis than a condenser enlarger.

An enlarger that scatters light before it strikes the negative, distributing light evenly on the negative. Detail is not as sharp as with a condenser enlarger; negative blemishes are minimised.

The property of materials which have a refractive index that varies according to the wavelength of light, i.e., bend the rays of some colors more than others; a prism placed in the path of a ray of white light bends the blue and violet rays more than the orange and red, so that it spreads out or "disperses" the colors as a continuous spectrum.

Even if the other possible aberrations were totally eliminated, images could result that still have a distorted appearance. For an example, an rectangle may appear as a barrel or pin cushion-shaped object. A lens aberration which does not affect the sharpness of the image, but alters the shape of objects; the inability of a lens to render straight lines perfectly straight; does not improve by stopping down the lens; there are two types of distortion:

Barrel: Straight lines are bowed in at the edges of the picture frame re sembling the sides of a barrel; pres ent in small amounts in some wideangle or wideangle-zoom lenses, bu~ uncorrected in fisheye lenses.

Pincushion: The opposite of barrel distortion; straight lines are bowed in toward the middle to resemble the sides of a pincushion; present in smal amounts in some telephoto and telephoto-zoom lenses.

Holding back the image-forming light from a part of the image projected on an enlarger easel during part of the basic exposure time to make that area of the print lighter.

Two pictures taken on one frame of film, or two images printed on one piece of photographic paper. Some cameras can have double exposure level depressed with multiple exposures one even with a motor drive.

E