PHOTOGRAPHY TERMINOLOGY

Aperture: Lens opening. The hole or opening formed by the metal leaf diaphragm inside the lens or the opening in a camera lens through which light passes to expose the film. The size of aperture is either fixed or adjustable. Aperture size is usually calibrated in f- numbers-the larger the number, the smaller the lens opening. Aperture affects depth of field, the smaller the aperture, the greater is the zone of sharpness, the bigger the aperture, the zone of sharpness is reduced. The hole or opening formed by the metal leaf diaphragm inside the lens; controls amount of light and depth of field, prevents vignetting and reduces lens aberrations; the size of the aperture is indicated by its f-number, i.e., the ratio of the diameter of the opening to the focal length of the lens; a large aperture is indicated by a small numerical f-number.

ASA: American Standards Association. Group that determining numerical ratings of speed for US made photosensitive products. e.g. films. In 1982, its role and its influence was narrow down by the establishment of the ISO (International Standards Organization).

Backlighting: Light coming from behind the subject, toward the camera lens, so that the subject stands out vividly against the background. Sometimes produces a silhouette effect. Always use something (a hand, a lens shade to avoid the light falls onto the lens - to avoid lens flares).

Camera shake:
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.

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

CompactFlash: Most digital cameras with PC Card interfaces use a storage technology called Compact Flash. Standard supported by the Compact Flash Association. Compact Flash is ATA compatible and will fit into any Type II or Type III slot when used with a passive adapter.

Contrast: 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.

Depth of Field: 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, wide-angle lenses have inherently more depth of field at each f-number and telephoto lenses have less.

F-number: The numbers on the lens aperture ring and the camera's LCD (where applies) that indicate the relative size of the lens aperture opening. The f-number series is a geometric progression based on changes in the size of the lens aperture, as it is opened and closed. As the scale rises. each number is multiplied by a factor of 1.4. The standard numbers for Calibration are 1.0,1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, etc., and each change results in a doubling or halving of the amount of light transmitted by the lens to the film plane. Basically, calculated from the focal length of the lens divided by the diameter of the bundle of light rays entering the lens and passing through the aperture in the iris diaphragm.

Film Speed: Indicated by a number such as ISO 100 or ISO 400 etc. The sensitivity of a given film to light,. The higher the number, the more sensitive or faster (and more grainer) the film. Note: ISO stands for International Standards Organization.

Ghost images: Bright spots of light, often taking the shape of the aperture, which appear in the camera viewfinder or in the final photograph when a lens is pointed at a bright light like the sun; controllable through the use of multilayer coating of the lens elements.

ISO Speed: The international standard for representing film sensitivity. The emulsion speed (sensitivity) of the film as determined by the standards of the International Standards Organization. In these standards, both arithmetic (ASA) and logarithmic (DIN) speed values are expressed in a single ISO term. For example, a film with a speed of ISO 100/21° would have a speed of ASA 100 or 21 DIN. The higher the number, the greater the sensitivity, and vice versa. A film speed of ISO 200 is twice as sensitive as ISO 100, and half that of ISO 400 film.

LCD panel ( Liquid Crystal Display.): An electronically generated text, numeric & symbols. Before the popularity of the LCD, LED is the most common method. LCD consume only one fifth (1/5) of the power of the LED and thus have a wider application in photographic line. The only problem is, it'll turn dark at very high temperature (will resume to normal when cool down) and it will fades in extended time. (the Nikon F3 first used LCD display in 1980, I heard none is complaining about this after 17 years, did you ?) Used most commonly on cameras that shows such information as remaining exposures, flash status and aspect ratio selected.

Lens Speed: The largest lens opening (smallest f-number) at which a lens can be set. A fast lens transmits more light and has a larger opening than a slow lens. Determined by the maximum aperture of the lens in relation to its focal length; the "speed" of a lens is relative: a 400 mm lens with a maximum aperture of f/3.5 is considered extremely fast, while a 28mm f/3.5 lens is thought to be relatively slow.

Negative: The developed film that contains a reversed tone image of the original scene.

Processing: Developing, fixing, and washing exposed photographic film or paper to produce either a negative image or a positive image.

Sharpness: A term used to describe the ability of a lens to render fine detail clearly; dependent on the contrast and resolution of a lens and varies with the f/stop; in general, a lens is sharpest at the middle apertures. Also technically can be explained as clarity of the photographic image in terms of focus and contrast. Largely subjective but can be measured to some extent by assessing adjacency effects, i.e. the abruptness of the change in density between adjoining areas of different tone value.

Shutter: Blades, a curtain, plate, or some other movable cover in a camera that controls the time during which light reaches the film.

Single-Lens-Reflex (SLR) Camera: A type of camera that allows 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.

Telephoto Lens:  
A lens that makes a subject appear larger on film than does a normal lens at the same camera-to-subject distance. A telephoto lens has a longer focal length and narrower field of view than a normal lens and have a shallower depth of field than wide angle lenses. But it can do isolation of subject and have a longer reach without going near to the subject. Life can be very difficult in sports and wildlife photography. Telephoto lens whose focal length is longer than the diagonal of the film frame; in 35mm photography, lenses longer than 50-5Bmm; also referred to as a "long" lens.

Tripod:  
A three-legged supporting stand used to hold the camera steady. Especially useful when using slow shutter speeds and/or telephoto lenses. Another is the monopod, single leg tripod.

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.

Wide-Angle Lens: A lens that has a shorter focal length and a wider field of view (includes more subject area) than a normal lens. Also can explained as a lens whose focal length is shorter than the diagonal of the film frame; in 35mm photography, lenses shorter than 50mm; also referred to as a "short" lens.

Zoom Lens: A lens in which you adjust the focal length over a wide range of focal lengths. Substituting lenses of many focal lengths. Zoom lenses whose focal length is continuously variable over a certain range without a change in focus; its focal length is changed by operating a separate zoom or a combination focusing/zoom ring; difficult type of lens to design and manufacture, very useful for the photographer on a budget or one who likes to travel light.