تويت
الخطوة 1: العدسات الإضافية / زاوية الرؤية .. معدات وتقنيات إضافية .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
STEP 1 : ADDITIONAL LENSES / Angle of view
On some direct vision viewfinder and most single lens reflex cameras the lens barrel can be detached from the camera body . This enables you to change to lenses of other focal lengths . Most lenses attach and detach with a half - turn action others screw - on .
A single lens reflex camera is ideally suited for a range of lenses . Its through - the- lens focusing system shows you the altered amount of the subject the lens includes Direct vision viewfinder cameras must have additional frame lines for each lens marked in the viewfinder .
A basic set of three lenses are shown below . On a 35 mm camera these are typically a standard 50 mm lens , a short focal length , or " wide - angle " , lens of 28 or 35 mm and a long - focus , or " telephoto " . lens of 100 or 135 mm . These three form a useful set for most work , but for more specialized needs there are many inter- mediate lenses to choose from , as well as the more extreme wide - angle and telephoto types , discussed on pages 96-9 .
Having interchangeable lenses means that picture making can be extended in three important ways . First , you can change the amount of the subject included from the same camera position . Second , you can control the perspective in your pictures . Third , you can reduce or increase the depth of field , as explained on pages 94-5 .
Angle of view and focal length
On a standard 35 mm camera the angles taken in by 28 mm , 50 mm and 135 mm lenses are about 73 ° , 45 ° , and 20 ° respectively .
Lenses and picture areas
The angle of view is the amount of the subject that is included within the picture at any camera position . The three pictures , right , were all taken from the same camera pos- ition , shown in the diagram below . but with 28 mm , 50 mm , and 135 mm lenses . The sequence of pictures shows the dramatic effect that changing lenses has on the amount of the subject you can include in the picture .
With a 50 mm lens , center right . the angle of view is about the same as normal human vision . With a 28 mm short focal length lens , top right , more of the scene is included . but everything is reduced in size . A long focal length lens of 135 mm , bottom right , magnifies the main subject , so you fill your picture frame with a smaller area of the subject .
STEP 1 : ADDITIONAL LENSES / Angle of view
On some direct vision viewfinder and most single lens reflex cameras the lens barrel can be detached from the camera body . This enables you to change to lenses of other focal lengths . Most lenses attach and detach with a half - turn action others screw - on .
A single lens reflex camera is ideally suited for a range of lenses . Its through - the- lens focusing system shows you the altered amount of the subject the lens includes Direct vision viewfinder cameras must have additional frame lines for each lens marked in the viewfinder .
A basic set of three lenses are shown below . On a 35 mm camera these are typically a standard 50 mm lens , a short focal length , or " wide - angle " , lens of 28 or 35 mm and a long - focus , or " telephoto " . lens of 100 or 135 mm . These three form a useful set for most work , but for more specialized needs there are many inter- mediate lenses to choose from , as well as the more extreme wide - angle and telephoto types , discussed on pages 96-9 .
Having interchangeable lenses means that picture making can be extended in three important ways . First , you can change the amount of the subject included from the same camera position . Second , you can control the perspective in your pictures . Third , you can reduce or increase the depth of field , as explained on pages 94-5 .
Angle of view and focal length
On a standard 35 mm camera the angles taken in by 28 mm , 50 mm and 135 mm lenses are about 73 ° , 45 ° , and 20 ° respectively .
Lenses and picture areas
The angle of view is the amount of the subject that is included within the picture at any camera position . The three pictures , right , were all taken from the same camera pos- ition , shown in the diagram below . but with 28 mm , 50 mm , and 135 mm lenses . The sequence of pictures shows the dramatic effect that changing lenses has on the amount of the subject you can include in the picture .
With a 50 mm lens , center right . the angle of view is about the same as normal human vision . With a 28 mm short focal length lens , top right , more of the scene is included . but everything is reduced in size . A long focal length lens of 135 mm , bottom right , magnifies the main subject , so you fill your picture frame with a smaller area of the subject .
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