AE (Automatic Exposure)
AE-L (Automatic Exposure Lock)
Auto exposure Lock. Metering feature that used to hold the exposure setting when used in the automatic mode. Used most commonly in situation where off centering of the subject in composition and wish to retain the exposure setting of the subject OR where the level of exposure reading both the subject of interest and the background exposure reading is different eg. back lighting. Used to hold an automatically controlled shutter speed and/or aperture. Recommended when the photographer wants to control an exposure based on a scene's particular brightness area with Center Weighted or Spot Metering.
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 digital sensor. 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.
Aperture Priority
An exposure mode on an automatic or autofocus camera that lets you set the aperture while the camera sets the shutter speed for proper exposure. If you change the aperture, or the light level changes, the shutter speed changes automatically. Apart from the sport or action arena, aperture priority is the most common & effective automatic preference in photography. It can also explained as automatic exposure system in which the lens aperture is set by the photographer, and the camera sets the shutter speed. Can be used in the stop-down mode with any lens that does not interfere with the metering system.
ASA
American Standards Association. Group that determining numerical ratings of speed for US made photosensitive products. eg films. In 1982, its role and its influence was narrow down by the establishment of the ISO (International Standards Organisation).
Autofocus (AF)
System by which the camera lens (most popular) or the camera body (only available in Contax AX) automatically focuses the image of a selected part of the picture subject. The autofocus camera revolution first popularised with the launch of Minolta's Maxxium. Currently, most current SLRs are autofocus based.
AV
The Aperture value, usually refer to aperture settings.
B (Bulb) Setting
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.
Bracketing
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..
CompactFlash
Most digital cameras with PC Card interfaces use a storage technology called CompactFlash. Standard supported by the CompactFlash Association. CompactFlash is ATA compatible and will fit into any Type II or Type III slot when used with a passive adapter.
Component.
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.
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. 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.
CPU (it)
The electronic component that controls an electronic product's functions. Essentially, all Newer autofocus lenses have built-in CPUs to relay information relating to focal length, distance info, lens type to the camera body for exposure to AF processing.
Cropping
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.
Dedicated Flash
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).
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, 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.
Exposure
The quantity of light allowed to act on a photographic material; a product of the intensity (controlled by the lens opening) and the duration (controlled by the shutter speed) of light striking the digital sensor. The act of allowing light to reach the light-sensitive emulsion of the photographic material. Also refers to the amount (duration and intensity) of light which reaches the digital sensor.
Exposure bracketing :
Shooting the same subject at a range of different exposures. Some camera provides Auto Exposure Bracketing/Flash Exposure Bracketing.
Exposure compensation :
Exposure compensation for available light is activated by changing the shutter speed and/or lens aperture. This is done by using AE L AF-L (Auto Exposure/Autofocus Lock) button or exposure compensation button, or by Auto Exposure Bracketing . In flash photography with a dedicated TTL Speedliqht exposure compensation can also be performed by varying the amount of flash output. Camera-originated exposure compensation affects both the foreground subject and the background; variations in flash output amount affect only the foreground.
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 digital sensor 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.
f-stop
Useful for determining the maximum flash to-subject distance for flash photography.
Fill-flash :
A method of flash photography that combines flash illumination and ambient light, but does not attempt to balance these two types of illumination. Also see "balance fill flash".
Filter
A colored piece of glass or other transparent material used over the lens to emphasize, eliminate, or change the color or density (ND) of the entire scene or certain areas within a scene. Also see "colour temperature", "UV". Technically, it explained as a piece of material which restricts the transmission of radiation. Generally coloured to absorb light of certain colours. Can be used over light sources or over the camera lens. Camera lens filters are usually glass either dyed or sandwiching a piece of gelatin in a screw-in filter holder.
Flash
The artificial light souce in the dark. Electronic flash requires a high voltage, usually obtained from batteries through a voltage-multiplying circuit. It has a brief, intense burst of light, usually used where the lighting on the scene is inadequate for picture-taking. They are generally considered to have the same photographic effect as daylight. Most flash will correct the color temperature back to 5000 kelvin - the daylight color. You can play around with filters mounting on the flash head for some specific effects or alter the color if necessary. Modern flash has multiple TTL flash exposure control functions and even extend to autofocus control. Some specialized flash are high speed repeating flash which can use for strobocopic effect, UV-flash for ultra violet light photography etc.
f-Number
A number that indicates the size of the lens opening on an adjustable camera. The common f-numbers are f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22. The larger the f-number, the smaller the lens opening. In this series, f/1.4 is the largest lens opening and f/22 is the smallest. Also called f-stops, they work in conjunction with shutter speeds to indicate exposure settings. Also can be explained as numerical expression of the relative aperture of a lens at its different stops; equal to the focal length divided by the effective aperture of the lens opening and written in various forms, such as f/8, f8, 1: 8, etc.; each f-number is 1.4 times larger than the preceding one; each number indicates a halving or doubling of the amount of light allowed to pass through the lens; the next higher numbered f-number sign)fies an aperture which lets in exactly onehalf as much light, and the next lower number, twice as much light, i.e., f/11 lets in half as much light as f/8, while f/5.6 lets in twice as much; all lenses stopped down to the same f-number produce images of equal illumination (apart from differences due to varying reflection losses); therefore, for a given shutter speed, a given fnumber always corresponds to the same exposure.
f/stop
A fraction which indicates the actual diameter of the aperture: the "f" represents the lens focal length, the slash means "divided by," and the word "stop" is a particular f-number; for example, with a 50mm f/1.4 lens, the actual diameter of its maximum aperture is 50mm divided by 1.4 or 35.7mm; at f/2, the diameter becomes 50mm/2 or 25mm; at f/2.8, the aperture is 50mm/2.8 or 17.9mm across; as the numerical value of the f/stop increases, the aperture decreases in size.
Focus
Adjustment of the distance setting on a lens to define the subject sharply. Generally, the act of adjusting a lens to produce a sharp image. In a camera, this is effected by moving the lens bodily towards or away from the digital sensor or by moving the front part of the lens towards or away from the rear part, thus altering its focal length.
