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F
- F-number
- The number resulting when the focal length of a lens is divided by the diameter of the aperture. A sequence of f-numbers calibrates the aperture in regular steps (know as stops) between the minimum and maximum openings of the lens. The f-numbers generally follow a standard sequence, in such a way that the interval between one full stop and the next represents halving or doubling in the image brightness. Also called f-stop or relative aperture. The f-number becomes progressively higher as the aperture is reduced to allow in less light; i.e. f/5.6, f/8, f/11, f/16, f/22, f/32... Theoretically, all lenses at the same f-number produce images of equal brightness.
- F-stop
- A number that indicates the relative size of the opening of the lens (aperture) and written, for example, as f/16. Because the number is obtained by dividing the focal length of a lens by it's effective aperture, the larger the aperture, the smaller the f-number. In the conventional series, each number represents an aperture that admits half as much light as the preceding one. Thus f/16 lets half as much light as a lens opened to f/11.
- Factor
- See filter factor
- Fading
- The loss of or change of colour density, generally accelerated by exposure to sunlight.
- Falloff
- Decrease in the intensity of light as it spreads out from the source.
- Fast film
- Is film which has an emulsion that is very sensitive to light. These film have high ISO ratings.
- Fast lens
- Is a lens with a wide maximum aperture ( low f number ).
- Fat
- File Allocation Table. A table that an operating system maintains on a hard disk that provides a map of the clusters that a file has been stored in.
- Feathering
- A technique in many image editing programs that allows for the softening of the edge around a selection
- Fiber optics
- An optical system that uses glass or transparent plastic fibers as light transmitting media. These cables have greater bandwidth than electrical transmission through wires.
- Fiber-base
- Photographic papers without a plastic coating.
- Field curvature
- A lens aberration or defect that causes the image to be formed along a curve instead of on a flat plane.
- File Converters
- Hardware or software that is used to convert files from one type of file format to another format.
- File format
- The way a graphic file is saved. Several file format are available for use, and each one has its own advantage and disadvantage. The most popular file format include TIFF, PICS' EPS, BMP, JPEG. TIFF is the most widely used file format.
- File server
- A computer on a local area network that is used to store files that are shared among the users on the network.
- File size
- The file size of an image is proportional to its resolution. The higher the resolution, the bigger the file size. File size is different from image size.
- Fill-flash
- A technique that uses flash illumination as a supplement to ambient light. Useful when photographing subjects that are backlit, with very high-contrast lighting or in shadow.
- Fill-in
- Secondary light source used to fill in the shadow created by the main or key light. Called fill-in flash when electronic flash is used.
- Film
- The material used in a camera to record a photographic image. Generally it is a light-sensitive emulsion coated on a flexible acetate or plastic base.
- Film base
- Flexible support on which light sensitive emulsion is coated.
- Film clips
- Metal or plastic clips used to prevent the curling of the film during the drying.
- Film holder
- A light-tight, removable device for holding film on many medium-format. This allows the photographer to preload the film so he can quickly change rolls of film.
- Film leader
- Length of protective film at the beginning of a roll of unexposed or processed film.
- Film plane
- The plane on which the film lies in a camera. The camera lens is designed to bring images into focus precisely at the film plane in a camera to ensure correctly exposed pictures.
- Film pressure plate
- A part of the camera back which, when closed against the film guide rails, creates a very precise tunnel in which the film is flatly positioned for sharpness.
- Film recorder
- A device used to output digital files onto film materials. CRT film recorders use a cathode ray tube and RGB filters to create the film image. Drum-based film recorders/writers include sheet-fed and roll-fed models and use white light or lasers to record the image on film.
- Film scanner
- A device that scans slides and negatives to create a digital image.
- Film speed
- A film's sensitivity to light, rated numerically so that it can be match to the camera's exposure control. Film speed ratings increase as the sensitivity of the film increases. Each time you double the film speed, half as much light is needed for correct exposure. Faster films need less light but they produce grainier pictures. Slower films have a finer grain and they produce more contrast. Pictures taken on slower films are sharper in appearance.
- Film trailer
- Length of protective film beyond the exposed area of a roll of film.
- Filter
- 1. A piece of coloured glass, plastic, or other material that selectively absorbs some of the wavelengths of light passing through it. Some filters affect colour or tone other can, for example, cut out unwanted reflections, help to reduce haze or to be used to create a variety of special effects. 2. To use such a filter to modify the wavelengths of light reaching a light-sensitive material.
- Filter factor
- The increased exposure needed to compensate for the amount of light absorbed by a filter. A factor of two indicates you need to give the film one stop more exposure; a factor of three needs two stops and a factor of six needs three stops more.
- Filter pack
- Several filters used together, as in a enlarger for colour printing or when duplicating slides, in order to obtain the best or desired colour in the image.
- Fine grain
- Film or developer that produces images in which areas of uniform tone appear smooth, with no clumping of the silver particles that form the image.
- Fine grain developers
- Are film developers which help to keep grain size in the photographic image to a minimum.
- Firewall
- A firewall is a program, usually an internet gateway server, which protects the resources of one network from users from other networks.
- Firewire
- A very fast external bus that supports data transfer rates of up to 400 Mbps. Firewire was developed by Apple and falls under the IEEE 1394 standard. Other companies follow the IEEE 1394 but have names such as Lynx and I-Link.
- Fish-eye lens
- Extreme wide-angle lens with an angle of view exceeding 100 degree and sometimes in excess of 180 degree. depth of field is practically infinite and focusing is not required.
- Fixed focal length
- Used to describe a camera with a non-removable, non-zoom lens. Because of this, the lens focal length cannot be changed.
- Fixed focus
- A camera where focus is not adjustable.
- Fixer
- A chemical solution (sodium thiosulfate or ammonium thiosulfate) that makes a photographic image sensitive to light. The fixer stabilizes the emulsion by converting the undeveloped silver halides into water-soluble compounds, which can then be dissolved away. Also called hypo.
- Flare
- The soft effect visible in a picture resulting from stray light which passes through the lens but is not focused to form the primary image. Flare can be controlled by using optical coating, light baffles and low reflection surfaces , or a lens hood.
- Flash bracket
- When working with a flash in a situation where the final product is desired to be of better quality than a snapshot and a flash is needed, a flash bracket is a necessity. A flash bracket will allow the flash to be positioned directly above the camera to help to eliminate the harsh shadows that are often seen in simple snap shots.
- Flash card
- A memory card that works with the flash memory, allowing the camera to retain data after the system has been turned off.
- Flash duration
- Refers to the amount of time it takes for a flash to fire. Flash duration typically varies from about 1/1000 to 1/20,000 sec.
- Flash factor
- Is a number which provides a guide to correct exposure when using Flash. See also Guide number
- Flash memory
- A memory chip that has the ability to retain image data even after the host system has been shut off; this feature insures that, even if the digital camera's batteries die, the image data will remain stored in the camera's memory. Fringing: Fringing occurs when a digital image is sharpened. The term usually refers to a white fringe appearing on the edges of objects in the image. Fringing can also occur as a result of compression.
- Flash meter
- A device for measuring the light coming from a electronic flash and indicating the appropriate aperture for correct exposure. Some flash meter can also measure the ambient light.
- Flash range
- The maximum distance from which a flash can effectively illuminate a subject. Most built-in flashes are effective to about 12-15 feet. Range varies by brand, so check the specification carefully.
- Flash shooting distance range
- The distance range over which a flash can effectively provide light. Flash shooting distance range is controlled by the amount of flash output available. Each automatic Speedlight's flash output varies from maximum duration to minimum duration Close-up subjects will require lower (to minimum) output while more distant subjects will require more light up to the maximum output. The flash shooting distance range varies with the aperture, film speed, etc.
- Flash sync
- A special socket on a camera that allows the attachment of an auxiliary strobe light for flash pictures. It is synchronized to the camera's shutter so the light goes off at the right time.
- Flashing
- Pre-exposing the paper to a very diffused white light in order to reduce the contrast level between the highlights and shadows and extend the tonal range.
- Flat
- A scene, negative, or print with very little difference in brightness between light and dark areas.
- Flatbed scanner
- An optical scanner in which the original image remains stationary while the sensors (usually a CCD linear array) passes over or under it. The scanned material is held flat rather than being wrapped around a drum.
- Flatten
- To combine together multiple layers and other elements of a digitally manipulated or composite image into one. Usually final step of working with layers prior to saving images in standard image format. Otherwise, save must be in native format.
- Flicker
- A perceivable fluctuation of the brightness levels of a displayed image. This problem is often present in CRT monitors that have a vertical scan rate that is lower than 50 Hz.
- Floating selection
- A moveable selection that is active and above a layer. A floating selection can be manipulated without affecting the pixel data underneath it.
- Floodlight
- An electric light designed to produce a broad, relatively diffused beam of light.
- Focal length
- The distance, usually given in millimeters, between the optical center of a lens and the point at which rays of light from objects at infinity are brought to focus. In general, the greater the focal length, the smaller and more magnified the part of the scene, it includes in the picture frame.
- Focal plane
- The plane on which the image of a subject is brought to focus behind the lens. To produce a sharp picture, the lens must be focused so that this place coincides with the plane on which the film sits. Also called the film plane.
- Focal point
- The point on the optical axis where light rays form a sharp image of a subject. An ideal lens would allow light rays to diverge from a subject parallel to the optical axis and converge to a point when they pass through the lens.
- Focal range
- In photography, the portion of an object that is in focus. Also called Depth of field.
- Focal- plane shutter
- A camera mechanism that admits light to expose film by moving a slit or opening in a roller blind just in front of the film (focal) plane.
- Focus
- Position in which rays of light from a lens converge to form a sharp image.
- Focus Range
- The range within which a camera is able to focus on the selected picture subject - 4 feet to infinity - for example.
- Focus Tracking
- Enables the camera to analyze the speed of the movi ing subject according to the focus data detected, and to obtain correct focus by anticipating the subject's position and driving the lens to that position&emdash;at the exact moment of exposure, basically a Nikon's and Canon's feature. Currently, Nikon lead the pack in this tecnology with the F5, the fastest among all.
- Focus-Priority for autofocus
- Shutter cannot be released until the subject s in focus. For situations when an in-focus subject s important. With the F5 camera body, Focus-Priority s given to Single Servo AF mode while Release-Priority is given to Continuous Servo AF. Using Custom Setting, however, you can change the priority to Release-Priority Single Servo AF or Focus-Priority Continuous Servo AF.
- Focusing
- System of moving the lens in relation to the image plane so as to obtain the required degree of sharpness of the film.
- Focusing cloth
- A dark cloth used in focusing a view camera. The cloth fits over the camera back and the photographer's head to keep out light and to make the ground glass image easier to see.
- Focusing screen
- Used for focusing on a subject or composing a picture; the focusing screen is located at a position equivalent to that of the film plane. To provide dispersion, a matte field made of specially ground glass or plastic is generally used for focusing screens.
- Fog
- An overall density in the photographic image cause by unintentional exposure to light or unwanted chemical activity.
- Foreground
- Area in an image closer than the main subject.
- Foreground colour
- This is the colour that is used when painting, filling, and creating text.
- Formatting
- Completely erasing and resetting a camera's memory card. This is usually done as a quick way to erase a full card that you want to reuse or to attempt to fix a card that can't be recognized by the digital camera.
- Four-colour process
- Colour printing with cyan, magenta, yellow, and black inks.
- Fps
- Frames per second. Used to describe how many frames can the motor drive or winder can handle automatically on winding per second consequently. Also apply to areas like video, animations, movie cameras.
- Fractal
- A mathematically generated pattern that is reproducible at any magnification or reduction.
- Fractal Image
- An image that is created by mathematically generated geometric shapes containing an infinite amount of image detail.
- Frame
- One picture on a roll of film.
- Frame Buffer
- An area in RAM memory set aside to specifically hold the data for the screen display.
- Fresnel
- Pattern of a special form of condenser lens consisting of a series of concentric stepped rings, each ring a section of a convex surface which would, if continued, form a much thicker lens. Used on focusing screens to distribute image brightness evenly over the screen.
- Fringing
- This occurs when a digital image is artificially sharpened. The term usually refers to a white fringe that is apparent on the edges of objects in the picture. Fringing can also occur as a result of compression.
- FTP
- File Transfer Protocol. This is the language used for file transfer from computer to computer across the WWW. An anonymous FTP is a file transfer between locations that does not require users to identify themselves with a password or log-in. An anonymous FTP is not secure, because it can be accessed by any other user of the WWW.
- Full frame
- Show all of the image; mask to image on sides if necessary. Also, "NC": no crop on photo required.
- Full scale
- Describes a print having a wide range of tonal values from deep, rich black through many shades of gray to brilliant white
- Full stop
- A change in aperture or shutter speed that admits half as much or twice as much light.
- Fuzziness
- The amount of anti-aliasing along the edges of a selection.
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