تويت
المرشد خطوة بخطوة للتصوير الفوتوغرافي .. المصطلحات - الحرف / E - F - G - H/
Glossary
Terms in italics denote useful cross- references to other glossary entries .
/ E /
Electronic flash Light source produced when an electric current . stored in a capacitor , is discharged across two electrodes inside a gas- filled glass or quartz tube .
Electronic shutter Shutter where the mechanical mechanism used to control the period between opening and closing , is replaced by an elec- tronic timing circuit .
Emulsion In photography , the light- sensitive material , consisting of silver halides suspended in gelatin which is coated on to various bases to make plates , films , and printing paper .
Emulsion speed The sensitivity of an emulsion to light . Films are given ASA and DIN numbers denoting emulsion speed .
Enlargement A print which is larger than the negative used to produce it .
Enlarger Device for projecting and focusing a negative image on to sensitized printing paper . Prints of different sizes can be exposed by increasing or decreasing the distance between the negative and the printing paper .
Ever - ready case Camera case which need not be completely removed to operate the camera .
Expiry date Date stamp on the packaging of sensitized material indicating the date beyond which the manufacturer's guarantee of specification expires .
Exposure In most practical photo- graphy exposure is the product of the intensity of light that reaches the film ( controlled by the lens aperture ) and the length of time this intensity of light is allowed to act ( controlled by shutter speed ) .
Exposure latitude The amount by which you can over- or underexpose a light - sensitive material , and still produce an acceptable result .
Exposure meter Instrument for measuring the amount of light falling on or being reflected by a subject . It usually has means of converting the measurement into a range of shutter speed and aperture settings for the correct exposure .
Extension tube or ring Metal tube that fits between the lens and the camera body on small format cameras to extend the range of focusing for close - up photography .
/ F /
Fahrenheit scale Temperature scale on which 32 ° F is the freezing point of water and 212 ° F the boiling point .
Fill - in light Direct or reflected light used to illuminate shadows cast on the subject by the main light source .
Film Photographic material consis- ting of a thin , transparent plastic base coated with light - sensitive emulsion . It comes as a strip or in sheets .
Filter Transparent material , such as glass , acetate or gelatin , which modifies light passing through it . For example color filters selectively absorb certain wavelengths of light and allow others to pass through . Filters affect the exposure of light- sensitive materials and are used at both camera and printing stages .
Filter factor Number by which an unfiltered exposure reading must be multiplied to give the same effective exposure through a filter . This compensates for the absorption of light by the filter .
Fine grain developer Film developer used to keep grain size in the image to a minimum by reducing the tendency of the image - forming silver to form clumps .
Fish - eye lens Extreme wide - angle lens uncorrected for barrel distortion .
Fixed focus Camera which has no focusing movement . The lens is usually set for the hyperfocal distance and is fitted with a small aperture . Subjects are sharp from about 6ft ( 2m ) to infinity .
Fixing Stage in film and print processing during which the photo- graphic image is stabilized so that it is no longer affected by light . Silver halides which have not been con- verted to black metallic silver during development are made soluble .
Fixing agent Chemical , normally sodium thiosulfate ( hypo ) used for fixing process .
Flare Non image forming light scattered by reflections within the lens , lens hood or the camera interior . It reduces image contrast and shadow detail .
Flash See Electronic flash .
Flashbulb Expendable glass bulb containing zirconium wire in oxygen . It burns out in a brilliant flash when ignited by low voltage current . Usually grouped in a flashcube or bar which allows four or more flashes before changing .
Flash synchronization Method of synchronizing the maximum light output of a flash source with the fully open period of the shutter . There are usually two settings on a camera : X and M.X is the settting for electronic flash and M is for flash bulbs .
Flat Subjective term used where contrast values are low . It is used to describe original lighting conditions , or a negative or positive image .
Floodlamp Light source producing a broad spread of diffused , even illumination over the subject .
fnumbers Number sequence on the lens barrel which is equivalent to the focal length divided by effective diameter of the aperture .
Focal length The distance between the rear nodal point of the lens and the focal plane , when the focus is set at infinity .
Focal plane The plane - normally flat and at right angles to the lens axis on which a sharp image is formed by the lens .
Focal plane shutter Shutter system using two blinds which lie just forward of the focal plane . Exposure is made when a gap between the blinds passes in front of the film . The gap width can be adjusted to control exposure .
Focal point Point at which all the rays of light transmitted by a lens from a given subject intersect to give an image in sharp focus .
Focus The point at which light rays passing through a lens converge to give a clear and sharply defined image of a given subject .
Focusing Method of moving the lens in relation to the camera back in order to form a sharp image on the film .
Focusing scale Distance scale marked on the focusing mechanism of a camera .
Focusing screen Ground glass or similar screen mounted in a camera to allow the image formed by the lens to be viewed and focused .
Fog Veil of density on a negative or print which does not form part of the image . It can be caused by chemicals or exposure to light .
Format Size and shape of the picture area of a photograph .
Frame ( 1 ) One of the images on a strip or roll of film area within a viewfinder which indicates the view received by the lens .
Fresnel lens Condenser lens consis- ting of a series of concentric , stepped rings . They are used on spotlights , to direct light rays into a concentrated beam , and behind focusing screens to give an evenly illuminated image .
/ G /
Gelatin Natural protein used to hold light - sensitive silver halide crystals in suspension and to bind them to the film or printing paper .
Glare Intense light reflected off highly reflective surfaces such as water , glass and very light toned subjects . It can be minimized by using a polarizing filter .
Glaze Glossy surface produced on some photographic printing papers by placing the wet print on to a heated drum or clean polished surface . Glazed prints have denser blacks than mat prints .
Glossy paper Printing paper with a smooth , shiny surface giving richer blacks than mat prints .
Gradation Contrast range in the tones of an image , from white through gray to black . It is described in terms of soft , where the tonal contrast is low ; normal ; and con- trasty where the contrast is great .
Grade Numerical description of the contrast characteristics of a range of printing paper . Similar grade numbers from different manufac- turers do not necessarily have equivalent contrast characteristics .
Grain Minute particles of black metallic silver , often clumped together , which are formed when silver halides have been exposed and developed .
Graininess Term used to describe the grainy appearance of a photo- graph caused when silver halide crystals clump together during development and become a visible irregular pattern of black silver upon enlargement . Graininess is most noticeable in even , gray areas of the image and depends on emulsion sensitivity and type of developer .
Ground glass screen Focusing screen etched on one side to give a translucent screen for viewing and focusing the image .
Guide number Figure used to determine the aperture pecessary with any particular subject to light source distance when a flash light source is in use . It takes into account the inverse square law .
/ H /
Halation Halos formed on the image around intensive highlights on the subject It is sometimes caused when light passed through the emulsion , strikes the back of the film and is reflected to the light- sensitive layer again .
Half - frame Format of 18mmx 24mm , half the size of the standard 35mm frame .
High key Photograph which contains predominantly pale tones .
Highlights Brightest , lightest parts of the subject . They appear as dense areas on the negative and reproduce as light areas on the positive .
Holography System of photography which does not require a camera or lens . Laser beams are used to create a three - dimensional image direct on to fine grain plates .
Hot shoe Fitting on top of a camera body to hold a flashgun . It contains electrical connections which automatically make contact between
flash gun and shutter synchronization circuit when the shutter release is fired , operating the flash .
Hue Title of a color . The property that distinguishes it from any other color ; i.e. red as distinct from purple .
Hyperfocal distance The distance nearest to the camera at which a subject is sharp when the lens is focused on infinity .
Hypo Historical but still common name for the fixing agent , sodium thiosulfate .
Hypo eliminator ( Clearing agent ) Chemical bath used to destroy fixing agent from an emulsion , and so hasten washing .
Glossary
Terms in italics denote useful cross- references to other glossary entries .
/ E /
Electronic flash Light source produced when an electric current . stored in a capacitor , is discharged across two electrodes inside a gas- filled glass or quartz tube .
Electronic shutter Shutter where the mechanical mechanism used to control the period between opening and closing , is replaced by an elec- tronic timing circuit .
Emulsion In photography , the light- sensitive material , consisting of silver halides suspended in gelatin which is coated on to various bases to make plates , films , and printing paper .
Emulsion speed The sensitivity of an emulsion to light . Films are given ASA and DIN numbers denoting emulsion speed .
Enlargement A print which is larger than the negative used to produce it .
Enlarger Device for projecting and focusing a negative image on to sensitized printing paper . Prints of different sizes can be exposed by increasing or decreasing the distance between the negative and the printing paper .
Ever - ready case Camera case which need not be completely removed to operate the camera .
Expiry date Date stamp on the packaging of sensitized material indicating the date beyond which the manufacturer's guarantee of specification expires .
Exposure In most practical photo- graphy exposure is the product of the intensity of light that reaches the film ( controlled by the lens aperture ) and the length of time this intensity of light is allowed to act ( controlled by shutter speed ) .
Exposure latitude The amount by which you can over- or underexpose a light - sensitive material , and still produce an acceptable result .
Exposure meter Instrument for measuring the amount of light falling on or being reflected by a subject . It usually has means of converting the measurement into a range of shutter speed and aperture settings for the correct exposure .
Extension tube or ring Metal tube that fits between the lens and the camera body on small format cameras to extend the range of focusing for close - up photography .
/ F /
Fahrenheit scale Temperature scale on which 32 ° F is the freezing point of water and 212 ° F the boiling point .
Fill - in light Direct or reflected light used to illuminate shadows cast on the subject by the main light source .
Film Photographic material consis- ting of a thin , transparent plastic base coated with light - sensitive emulsion . It comes as a strip or in sheets .
Filter Transparent material , such as glass , acetate or gelatin , which modifies light passing through it . For example color filters selectively absorb certain wavelengths of light and allow others to pass through . Filters affect the exposure of light- sensitive materials and are used at both camera and printing stages .
Filter factor Number by which an unfiltered exposure reading must be multiplied to give the same effective exposure through a filter . This compensates for the absorption of light by the filter .
Fine grain developer Film developer used to keep grain size in the image to a minimum by reducing the tendency of the image - forming silver to form clumps .
Fish - eye lens Extreme wide - angle lens uncorrected for barrel distortion .
Fixed focus Camera which has no focusing movement . The lens is usually set for the hyperfocal distance and is fitted with a small aperture . Subjects are sharp from about 6ft ( 2m ) to infinity .
Fixing Stage in film and print processing during which the photo- graphic image is stabilized so that it is no longer affected by light . Silver halides which have not been con- verted to black metallic silver during development are made soluble .
Fixing agent Chemical , normally sodium thiosulfate ( hypo ) used for fixing process .
Flare Non image forming light scattered by reflections within the lens , lens hood or the camera interior . It reduces image contrast and shadow detail .
Flash See Electronic flash .
Flashbulb Expendable glass bulb containing zirconium wire in oxygen . It burns out in a brilliant flash when ignited by low voltage current . Usually grouped in a flashcube or bar which allows four or more flashes before changing .
Flash synchronization Method of synchronizing the maximum light output of a flash source with the fully open period of the shutter . There are usually two settings on a camera : X and M.X is the settting for electronic flash and M is for flash bulbs .
Flat Subjective term used where contrast values are low . It is used to describe original lighting conditions , or a negative or positive image .
Floodlamp Light source producing a broad spread of diffused , even illumination over the subject .
fnumbers Number sequence on the lens barrel which is equivalent to the focal length divided by effective diameter of the aperture .
Focal length The distance between the rear nodal point of the lens and the focal plane , when the focus is set at infinity .
Focal plane The plane - normally flat and at right angles to the lens axis on which a sharp image is formed by the lens .
Focal plane shutter Shutter system using two blinds which lie just forward of the focal plane . Exposure is made when a gap between the blinds passes in front of the film . The gap width can be adjusted to control exposure .
Focal point Point at which all the rays of light transmitted by a lens from a given subject intersect to give an image in sharp focus .
Focus The point at which light rays passing through a lens converge to give a clear and sharply defined image of a given subject .
Focusing Method of moving the lens in relation to the camera back in order to form a sharp image on the film .
Focusing scale Distance scale marked on the focusing mechanism of a camera .
Focusing screen Ground glass or similar screen mounted in a camera to allow the image formed by the lens to be viewed and focused .
Fog Veil of density on a negative or print which does not form part of the image . It can be caused by chemicals or exposure to light .
Format Size and shape of the picture area of a photograph .
Frame ( 1 ) One of the images on a strip or roll of film area within a viewfinder which indicates the view received by the lens .
Fresnel lens Condenser lens consis- ting of a series of concentric , stepped rings . They are used on spotlights , to direct light rays into a concentrated beam , and behind focusing screens to give an evenly illuminated image .
/ G /
Gelatin Natural protein used to hold light - sensitive silver halide crystals in suspension and to bind them to the film or printing paper .
Glare Intense light reflected off highly reflective surfaces such as water , glass and very light toned subjects . It can be minimized by using a polarizing filter .
Glaze Glossy surface produced on some photographic printing papers by placing the wet print on to a heated drum or clean polished surface . Glazed prints have denser blacks than mat prints .
Glossy paper Printing paper with a smooth , shiny surface giving richer blacks than mat prints .
Gradation Contrast range in the tones of an image , from white through gray to black . It is described in terms of soft , where the tonal contrast is low ; normal ; and con- trasty where the contrast is great .
Grade Numerical description of the contrast characteristics of a range of printing paper . Similar grade numbers from different manufac- turers do not necessarily have equivalent contrast characteristics .
Grain Minute particles of black metallic silver , often clumped together , which are formed when silver halides have been exposed and developed .
Graininess Term used to describe the grainy appearance of a photo- graph caused when silver halide crystals clump together during development and become a visible irregular pattern of black silver upon enlargement . Graininess is most noticeable in even , gray areas of the image and depends on emulsion sensitivity and type of developer .
Ground glass screen Focusing screen etched on one side to give a translucent screen for viewing and focusing the image .
Guide number Figure used to determine the aperture pecessary with any particular subject to light source distance when a flash light source is in use . It takes into account the inverse square law .
/ H /
Halation Halos formed on the image around intensive highlights on the subject It is sometimes caused when light passed through the emulsion , strikes the back of the film and is reflected to the light- sensitive layer again .
Half - frame Format of 18mmx 24mm , half the size of the standard 35mm frame .
High key Photograph which contains predominantly pale tones .
Highlights Brightest , lightest parts of the subject . They appear as dense areas on the negative and reproduce as light areas on the positive .
Holography System of photography which does not require a camera or lens . Laser beams are used to create a three - dimensional image direct on to fine grain plates .
Hot shoe Fitting on top of a camera body to hold a flashgun . It contains electrical connections which automatically make contact between
flash gun and shutter synchronization circuit when the shutter release is fired , operating the flash .
Hue Title of a color . The property that distinguishes it from any other color ; i.e. red as distinct from purple .
Hyperfocal distance The distance nearest to the camera at which a subject is sharp when the lens is focused on infinity .
Hypo Historical but still common name for the fixing agent , sodium thiosulfate .
Hypo eliminator ( Clearing agent ) Chemical bath used to destroy fixing agent from an emulsion , and so hasten washing .
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