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أنواع الكاميرات القياسية ..
تعرف على الكاميرات العاكسة للعدسة المزدوجة ..
كاميرات الصحافة ..
TWIN LENS REFLEX CAMERAS
A typical twin lens reflex camera is illustrated in Figure 19. The twin lens reflex camera is really two cameras in a single housing , one being used as a viewfinder and the other for taking the picture . The two lenses are carefully matched to have exactly the same focal length , so they produce exactly the same image size . The lenses are mounted together so that focusing the viewing lens automatically focuses the other lens .
From the top lens , the image is reflected by a mirror onto the viewing screen . From the bottom lens , the image is projected onto the film . Since the two lenses are completely separate , the viewing mirror is fixed in position so the picture can always be seen , even during exposure .
Figure 20 Twin lens reflex camera which uses interchangeable lenses .
As you will recall , whenever the viewing lens is separated from the camera lens , you have a parallax problem . The twin lens reflex does not solve this problem as the single lens reflex does . However , most modern twin lens reflex . cameras have built - in sliding masks or similar devices to compensate for parallax error throughout the normal focusing range of the camera .
Generally speaking , twin lens reflex cameras of this type use ordinary roll film and take 2 x 2 % pictures . This film is ordinarily sold in the 12 - exposure length , but for professional use it is also available in a 24 - exposure length . The longer film is made possible by omitting the paper backing for the film , using paper only at the beginning and end of the roll . Later model 24 x 24 cameras are designed to take the longer roll , but earlier models can often be modified by the manufacturer to take such rolls also .
The twin lens reflex is generally not designed to take interchangeable lenses . However , there are twin lens reflexes with interchangeable lenses for those who must have this feature in a camera of this type . ( Figure 20 ) Because both the viewing and taking lenses must have exactly the same focal length , they are always sold as a unit .
PRESS CAMERAS
The press or news photographer needs something quite special in his camera . He must have a sturdy piece of equipment which will take a lot of punishment . He needs a camera which will be set up to take pictures in a hurry . It must be practical for hand - held use as well as use on a tripod with groundglass focusing . There are two basic types of press cameras . One is exemplified by the American
A modern . press camera is much like earlier models although its construction has been modified and modernized from time to time . It is so flexible and universal a camera that it has become the recognized leader in its field among professional and advanced amateur photographers who want something that takes a larger film size and permits easy groundglass focusing and composition . It has , in actual fact , invaded the field that was once generally considered to be the exclusive province of the view camera , and to that end it has been provided with adjustments so that the lens can be raised , lowered , or shifted sideways to provide greater flexibility . Some cameras of this type also permit the back to be swung either vertically or horizontally to correct for perspective distortion or to increase the versatility of the camera under a wide range of conditions . The importance of these adjustments will be discussed much later in this course of study .
Figure 21 Heavy - duty press camera .
Figure 22 A non - bellows type press camera featuring . rapid film advance .
The term " press camera " as used here refers to a type of camera . As we have stated , most commercial and professional photographers use press cameras for a good many of their outdoor assignments . On the other hand , many newsmen prefer to use 35mm cameras for their newspaper photography . We make this point to illustrate the fact that personal preference is often a very important factor in the choice as to which camera to use for any specific job .
Figure 23 A modern view camera which is used for general commercial work .
أنواع الكاميرات القياسية ..
تعرف على الكاميرات العاكسة للعدسة المزدوجة ..
كاميرات الصحافة ..
TWIN LENS REFLEX CAMERAS
A typical twin lens reflex camera is illustrated in Figure 19. The twin lens reflex camera is really two cameras in a single housing , one being used as a viewfinder and the other for taking the picture . The two lenses are carefully matched to have exactly the same focal length , so they produce exactly the same image size . The lenses are mounted together so that focusing the viewing lens automatically focuses the other lens .
From the top lens , the image is reflected by a mirror onto the viewing screen . From the bottom lens , the image is projected onto the film . Since the two lenses are completely separate , the viewing mirror is fixed in position so the picture can always be seen , even during exposure .
Figure 20 Twin lens reflex camera which uses interchangeable lenses .
As you will recall , whenever the viewing lens is separated from the camera lens , you have a parallax problem . The twin lens reflex does not solve this problem as the single lens reflex does . However , most modern twin lens reflex . cameras have built - in sliding masks or similar devices to compensate for parallax error throughout the normal focusing range of the camera .
Generally speaking , twin lens reflex cameras of this type use ordinary roll film and take 2 x 2 % pictures . This film is ordinarily sold in the 12 - exposure length , but for professional use it is also available in a 24 - exposure length . The longer film is made possible by omitting the paper backing for the film , using paper only at the beginning and end of the roll . Later model 24 x 24 cameras are designed to take the longer roll , but earlier models can often be modified by the manufacturer to take such rolls also .
The twin lens reflex is generally not designed to take interchangeable lenses . However , there are twin lens reflexes with interchangeable lenses for those who must have this feature in a camera of this type . ( Figure 20 ) Because both the viewing and taking lenses must have exactly the same focal length , they are always sold as a unit .
PRESS CAMERAS
The press or news photographer needs something quite special in his camera . He must have a sturdy piece of equipment which will take a lot of punishment . He needs a camera which will be set up to take pictures in a hurry . It must be practical for hand - held use as well as use on a tripod with groundglass focusing . There are two basic types of press cameras . One is exemplified by the American
A modern . press camera is much like earlier models although its construction has been modified and modernized from time to time . It is so flexible and universal a camera that it has become the recognized leader in its field among professional and advanced amateur photographers who want something that takes a larger film size and permits easy groundglass focusing and composition . It has , in actual fact , invaded the field that was once generally considered to be the exclusive province of the view camera , and to that end it has been provided with adjustments so that the lens can be raised , lowered , or shifted sideways to provide greater flexibility . Some cameras of this type also permit the back to be swung either vertically or horizontally to correct for perspective distortion or to increase the versatility of the camera under a wide range of conditions . The importance of these adjustments will be discussed much later in this course of study .
Figure 21 Heavy - duty press camera .
Figure 22 A non - bellows type press camera featuring . rapid film advance .
The term " press camera " as used here refers to a type of camera . As we have stated , most commercial and professional photographers use press cameras for a good many of their outdoor assignments . On the other hand , many newsmen prefer to use 35mm cameras for their newspaper photography . We make this point to illustrate the fact that personal preference is often a very important factor in the choice as to which camera to use for any specific job .
Figure 23 A modern view camera which is used for general commercial work .
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