تويت
الضوء في التصوير عن قرب .. مصدر الضوء .. كيفية التقاط وتطوير الصور الملونة
LIGHT IN CLOSE - UP
Close - up images have a special appeal in photography , because they open up a fresh visual area . The relative ease with which a camera can be used to probe small scales brings a world of patterns and scenes that we do not normally see . The small scale makes it possible to control the lighting exactly , whether using natural lighting , flash or photographic lamps . There are , however , some special problems and precautions .
Close - up photography begins at the point below which a normal lens cannot focus . This is normally just a few feet , and the greatest reproduction ratio ( the ratio of the image to the subject size ) is about 1 : 7 . To close in more needs either a supplementary magnifying lens attached to the camera lens , or some means of moving the camera lens forward from the body and away from the film plane . The choice of close - up equipment reflects this : there are supplementary close - up lenses for modest magnifications , macro lenses that have especially long focusing mechanisms , extension rings and extension bellows .
Extending the lens from the film is the basic way of getting a magnified image , but it also reduces the amount of light that reaches the film . So , the greater the magnification , the more compensation is needed , either by opening the lens aperture or by increasing the exposure time . Alternatively , increasing the strength of the light or bringing it closer will make up the difference .
kind of camera you use , and on the type of lighting . If you measure the light reaching the film , as does a TTL meter , the exposure settings will be accurate . Otherwise , some calculation is needed ( see box ) . With flash , if you have a dedicated unit and the reading is made off the film plane , rather than from an epso , there are no problems . Otherwise , position the flash according to the formula given in the box .
ABOVE Normal lenses do not have the close - focus capability required for true macro photography . However , shots such as this are quite possible with normal lenses if extension rings or extension bellows are added .
Macro lens
This 60mm macro lens has an angle of view of 39 ° and a wide focusing range from infinity down to 27cm , giving a maximum reproduction scale of 1 : 2 . By adding the accompanying extension ring , the reproduction scale can be increased to 1 : 1 . In addition , the maximum aperture of f2.8 is wide enough for most general applications .
Allowing for the Lens Extension
The following formula gives the increase in exposure . Translate this into f - stops by means of the table below .
Exposure increase =
( Lens focal length + Extension ) × 2 /
Lens focal length
Alternatively , if you use flash , position it according to this formula :
Flash - to subject distance =
Flash guide number / Aperture x
( Magnification + 1 )
Exposure increase and f - stops
EXPOSURE INCREASE
INCREASE IN F - STOPS
RIGHT The real attraction of close - up photography is the way it can open up a whole new world ; objects or aspects of objects that may otherwise have been ignored take on a new light .
BELOW In general , hot - shoe mounted flashguns are not suited to close - up work . Ring - flash units , which can be attached to the front of your camera's light , provide the even lighting necessary .
LIGHT IN CLOSE - UP
Close - up images have a special appeal in photography , because they open up a fresh visual area . The relative ease with which a camera can be used to probe small scales brings a world of patterns and scenes that we do not normally see . The small scale makes it possible to control the lighting exactly , whether using natural lighting , flash or photographic lamps . There are , however , some special problems and precautions .
Close - up photography begins at the point below which a normal lens cannot focus . This is normally just a few feet , and the greatest reproduction ratio ( the ratio of the image to the subject size ) is about 1 : 7 . To close in more needs either a supplementary magnifying lens attached to the camera lens , or some means of moving the camera lens forward from the body and away from the film plane . The choice of close - up equipment reflects this : there are supplementary close - up lenses for modest magnifications , macro lenses that have especially long focusing mechanisms , extension rings and extension bellows .
Extending the lens from the film is the basic way of getting a magnified image , but it also reduces the amount of light that reaches the film . So , the greater the magnification , the more compensation is needed , either by opening the lens aperture or by increasing the exposure time . Alternatively , increasing the strength of the light or bringing it closer will make up the difference .
kind of camera you use , and on the type of lighting . If you measure the light reaching the film , as does a TTL meter , the exposure settings will be accurate . Otherwise , some calculation is needed ( see box ) . With flash , if you have a dedicated unit and the reading is made off the film plane , rather than from an epso , there are no problems . Otherwise , position the flash according to the formula given in the box .
ABOVE Normal lenses do not have the close - focus capability required for true macro photography . However , shots such as this are quite possible with normal lenses if extension rings or extension bellows are added .
Macro lens
This 60mm macro lens has an angle of view of 39 ° and a wide focusing range from infinity down to 27cm , giving a maximum reproduction scale of 1 : 2 . By adding the accompanying extension ring , the reproduction scale can be increased to 1 : 1 . In addition , the maximum aperture of f2.8 is wide enough for most general applications .
Allowing for the Lens Extension
The following formula gives the increase in exposure . Translate this into f - stops by means of the table below .
Exposure increase =
( Lens focal length + Extension ) × 2 /
Lens focal length
Alternatively , if you use flash , position it according to this formula :
Flash - to subject distance =
Flash guide number / Aperture x
( Magnification + 1 )
Exposure increase and f - stops
EXPOSURE INCREASE
INCREASE IN F - STOPS
RIGHT The real attraction of close - up photography is the way it can open up a whole new world ; objects or aspects of objects that may otherwise have been ignored take on a new light .
BELOW In general , hot - shoe mounted flashguns are not suited to close - up work . Ring - flash units , which can be attached to the front of your camera's light , provide the even lighting necessary .
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