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الخطوة 3: ملحقات التصوير عن قرب .. معدات وتقنيات إضافية .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
STEP 3 : CLOSE - UP ATTACHMENTS
Most focusing mounts do not allow the lens to move far enough forward to focus sub- jects closer than about 12 ins ( 30 cm When you want to work close - up there are four devices you can use to solve this : an extension ring or tube , a bellows attach ment , a close - up lens , or a " macro " lens .
use a standard 50 mm lens . Do not use long or very short focal length lenses unless they have a " macro " setting on the focusing ring . This repositions the lens elements , en- abling you to work close - up . Zoom lenses are unsuitable as they will not hold sharp focus with close - up attachments .
Macro lenses
If you want to do a lot of close - up work , it is easiest to use a macro lens . Most of these are 50 mm lenses . With them you can ex- tend the lens to twice its focal length , or more , from the film . At two focal lengths from the film the lens will focus the subject at its correct size . Further extension of the lens magnifies the subject .
Lens elements and extension attachments
A close - up lens fits over the front of a stand- ard lens . It converges the light rays before they reach the camera lens , so that very close subjects can be brought into focus .
If your camera has a detachable lens you can use extension attachments between the lens and the camera.body - rings , tubes , or bellows to work close - up . You still use the focusing ring on the lens for focusing . All attachments that fit between the lens and the camera reduce the amount of light reaching the film . To compensate , you should multiply the exposure by the factors shown in the table on the opposite page . This is not necessary if you have through- the - lens metering .
An extension bellows , shown right , is more versatile than rings or tubes . It fits between the lens and the camera to allow continuous focusing .
Close - up accessories
Some useful equipment for working close - up is shown right . A tripod - either a standard or table - top size is important to keep the camera absolutely steady . You will often have to use very slow shutter speeds , to compensate when the lens is stopped down to improve the depth of field . A cable release also reduces the possibility of camera shake . A tape measure enables you to calculate the increase required in the exposure if you do not have through - the - lens metering .
Equipment for working close - up
Tripod
Table top tripod
Cable release
Extension tubes
Ball and socket tripod head
Tape measure
Bellows extension
Close - up attachments and image intensity
When you use a close - up attach- ment to increase the distance be- tween the lens and film the image becomes dimmer . Doubling the lens - film distance quarters the light . The same amount of light comes through the lens , but because it is spread over a larger area , as shown right , less reaches the film .
A through - the - lens meter will measure the reduced light ; but if you use any other sort of exposure meter you must multiply the read- ing by the relevant factor given in the table below . The figures given only work for a 50 mm lens .
Exposure correction for close - up attachments
Subject distance
Lens extension
Magnification
Exposure factor
Magnification and close - up attachments
Closest normal focusing
A standard 50 mm lens will allow you to focus a subject sharply down to about 18 ins ( 46 cm ) . The flowers above were taken from this distance . Lenses on simple cameras will not even focus this close ( see p . 26 ) . In this series , the text refers to image size on the film . The prints shown are enlarged x 2 .
Standard lens
Magnification by one quarter
With a close - up lens attachment you can move in to about 9 ins ( 23 cm ) from the subject . This is close enough to magnify the image to one quarter life size on the The extra lens reduces the image quality slightly . Sharpness is maximized if you stop the lens down .
Close - up lens attachment
Magnification by one half
The picture above was taken using a standard lens with a reversing ring extension tube . The lens was 6 ins ( 15 cm ) from the subject . giving an image half life size . The ring enables the lens to be reversed so that it is attached to the camera body by its filter thread .
Reversing ring
Magnification by one
One short plus one long extension tube position the lens twice its usual distance from the film . The image on the film is now the same size as the subject . Distances from subject to lens , and lens to film , are both 4 ins ( 10 cm ) . Depth of field is very shallow so focusing is critical .
Two extension . tubes
Magnification by one and a half
A whole set of extension tubes allows still closer approach , to about 3 ins ( 8.3 cm ) from the subject . The lens is two and a half times its focal length from the film , and the image is increased to one and a half times the size of the subject .
Set of extension tubes
Magnification by two and a half
Fully extended , the bellows unit below positions the camera lens three and a half times its focal length from the film . The lens is about 21 ins ( 7 cm ) from the subject . giving an image two and a half times life size . For such magnifica tions , photographers often use a reversing ring with the bellows or a macro lens .
Bellows extension
Reminders : lenses and attachments
Wide - angle lenses increase the amount of the scene that is included
A short focus , wide - angle , lens gives a wider angle of view and a greater depth of field than a normal lens . The shorter the focal length , the more the image is distorted toward the edges of the picture frame .
Long - focus lenses magnify and reduce the amount of the scene that is included
A long focus lens fills the picture with a small area of the scene . It has a shallow depth of field .
Perspective is altered by changing camera distance and lens
Changing subject distance and lens changes the apparent perspective in a picture . If you change your viewpoint to fill the frame , a long focus lens will tend to eliminate perspec- tive and a wide - angle lens increase it .
Colored filters alter the tonal balance in black and white photography
Colored filters lighten their own colors and darken complementary colors .
To work close - up you must increase the distance between the lens and film
To work closer than about 12 ins ( 30 cms ) use a stan- dard 50 mm lens with exten- sion tubes , a close - up attachment , or bellows ; or change to a " macro " lens . If you do not have through- the - lens metering , increase exposure .
STEP 3 : CLOSE - UP ATTACHMENTS
Most focusing mounts do not allow the lens to move far enough forward to focus sub- jects closer than about 12 ins ( 30 cm When you want to work close - up there are four devices you can use to solve this : an extension ring or tube , a bellows attach ment , a close - up lens , or a " macro " lens .
use a standard 50 mm lens . Do not use long or very short focal length lenses unless they have a " macro " setting on the focusing ring . This repositions the lens elements , en- abling you to work close - up . Zoom lenses are unsuitable as they will not hold sharp focus with close - up attachments .
Macro lenses
If you want to do a lot of close - up work , it is easiest to use a macro lens . Most of these are 50 mm lenses . With them you can ex- tend the lens to twice its focal length , or more , from the film . At two focal lengths from the film the lens will focus the subject at its correct size . Further extension of the lens magnifies the subject .
Lens elements and extension attachments
A close - up lens fits over the front of a stand- ard lens . It converges the light rays before they reach the camera lens , so that very close subjects can be brought into focus .
If your camera has a detachable lens you can use extension attachments between the lens and the camera.body - rings , tubes , or bellows to work close - up . You still use the focusing ring on the lens for focusing . All attachments that fit between the lens and the camera reduce the amount of light reaching the film . To compensate , you should multiply the exposure by the factors shown in the table on the opposite page . This is not necessary if you have through- the - lens metering .
An extension bellows , shown right , is more versatile than rings or tubes . It fits between the lens and the camera to allow continuous focusing .
Close - up accessories
Some useful equipment for working close - up is shown right . A tripod - either a standard or table - top size is important to keep the camera absolutely steady . You will often have to use very slow shutter speeds , to compensate when the lens is stopped down to improve the depth of field . A cable release also reduces the possibility of camera shake . A tape measure enables you to calculate the increase required in the exposure if you do not have through - the - lens metering .
Equipment for working close - up
Tripod
Table top tripod
Cable release
Extension tubes
Ball and socket tripod head
Tape measure
Bellows extension
Close - up attachments and image intensity
When you use a close - up attach- ment to increase the distance be- tween the lens and film the image becomes dimmer . Doubling the lens - film distance quarters the light . The same amount of light comes through the lens , but because it is spread over a larger area , as shown right , less reaches the film .
A through - the - lens meter will measure the reduced light ; but if you use any other sort of exposure meter you must multiply the read- ing by the relevant factor given in the table below . The figures given only work for a 50 mm lens .
Exposure correction for close - up attachments
Subject distance
Lens extension
Magnification
Exposure factor
Magnification and close - up attachments
Closest normal focusing
A standard 50 mm lens will allow you to focus a subject sharply down to about 18 ins ( 46 cm ) . The flowers above were taken from this distance . Lenses on simple cameras will not even focus this close ( see p . 26 ) . In this series , the text refers to image size on the film . The prints shown are enlarged x 2 .
Standard lens
Magnification by one quarter
With a close - up lens attachment you can move in to about 9 ins ( 23 cm ) from the subject . This is close enough to magnify the image to one quarter life size on the The extra lens reduces the image quality slightly . Sharpness is maximized if you stop the lens down .
Close - up lens attachment
Magnification by one half
The picture above was taken using a standard lens with a reversing ring extension tube . The lens was 6 ins ( 15 cm ) from the subject . giving an image half life size . The ring enables the lens to be reversed so that it is attached to the camera body by its filter thread .
Reversing ring
Magnification by one
One short plus one long extension tube position the lens twice its usual distance from the film . The image on the film is now the same size as the subject . Distances from subject to lens , and lens to film , are both 4 ins ( 10 cm ) . Depth of field is very shallow so focusing is critical .
Two extension . tubes
Magnification by one and a half
A whole set of extension tubes allows still closer approach , to about 3 ins ( 8.3 cm ) from the subject . The lens is two and a half times its focal length from the film , and the image is increased to one and a half times the size of the subject .
Set of extension tubes
Magnification by two and a half
Fully extended , the bellows unit below positions the camera lens three and a half times its focal length from the film . The lens is about 21 ins ( 7 cm ) from the subject . giving an image two and a half times life size . For such magnifica tions , photographers often use a reversing ring with the bellows or a macro lens .
Bellows extension
Reminders : lenses and attachments
Wide - angle lenses increase the amount of the scene that is included
A short focus , wide - angle , lens gives a wider angle of view and a greater depth of field than a normal lens . The shorter the focal length , the more the image is distorted toward the edges of the picture frame .
Long - focus lenses magnify and reduce the amount of the scene that is included
A long focus lens fills the picture with a small area of the scene . It has a shallow depth of field .
Perspective is altered by changing camera distance and lens
Changing subject distance and lens changes the apparent perspective in a picture . If you change your viewpoint to fill the frame , a long focus lens will tend to eliminate perspec- tive and a wide - angle lens increase it .
Colored filters alter the tonal balance in black and white photography
Colored filters lighten their own colors and darken complementary colors .
To work close - up you must increase the distance between the lens and film
To work closer than about 12 ins ( 30 cms ) use a stan- dard 50 mm lens with exten- sion tubes , a close - up attachment , or bellows ; or change to a " macro " lens . If you do not have through- the - lens metering , increase exposure .
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