تويت
التصوير الفوتوغرافي الحديث
تصوير الخارجيات
تعديلات الكاميرا (الحركات)
CAMERA ADJUSTMENTS ( MOVEMENTS )
In no field of photography is the proper use of the various camera adjustments or movements so important as in architectural photography . The architectural photographer often has to work in very close quarters and it is necessary to resort to various tricks in order to get everything on the film . Fully as important is the requirement that the photographer must not distort the building . An architect or the real estate operator who wants to show a home to a prospective client will insist that the photograph be an accurate , undistorted likeness .
It is surprising how many commercial photographers use view camers without a clear idea of the movements they provide . Because of their importance to the architectural photographer , we will discuss these movements at this point , although the student will do well to remember that they can be used to excellent advantage in all types of photography . The modern commercial photographer who specializes in advertising work uses camera movements to a considerable extent .
RISING FRONT
This is the most commonly used of all movements . It permits you to raise the lens in relation to the film , so that you can get in the tops of tall buildings without the distortion produced when you tilt the camera . ( See Figures 1 , 2 , and 3. )
Figure 1 Skyscraper taken from street level with camera pointed straight forward to keep vertical lines in building from converging toward top . From this position , there is too much foreground and top of building is cut off .
Figure 2 Taken from same viewpoint with camera pointed up to get in all of building . Note that building seems to lean back because verti cal lines converge toward top .
Figure 3 Taken from same position as Figures 1 and 2 , but front of camera was raised to take i in top of building and to cut off most of the foreground .
FALLING FRONT
This permits you to lower the lens in relation to the film . Its principle of operation is the same as the rising front , except that it is used when the camera is at a height and the subject extends considerably below . This condition arises when you photograph a tall building from the roof of a neighboring and somewhat shorter building .
SLIDING FRONT
This is similar to the rising and falling front in operation , the difference being that the lens can be moved to either side .
It is important for the student to note that the use of the rising , falling , or sliding front does not in any way alter the perspective or introduce distortion . Just so the lens is not moved so far in any direction that it no longer covers the film , you can raise , lower , or slide the lens to either side as needed to get the image on the groundglass without giving thought to distortion .
VERTICAL SWING BACK
This is one of the most widely used of all camera movements in architectural photography . If your subject is too tall to be brought into the field of view of the camera , even with the lens raised as far as possible , you have no alternative but to tilt the camera upward . While this will bring the top of the building into the field of view , it will also cause the vertical lines in the building to converge at the top as shown in Figure 2 , which is highly undesirable . You must accept as one of the first principles of architectural photography that all vertical lines in a picture must be photographed as verticals ( except when you introduce perspective distortion purposely to achieve some specific result ) .
The only way to keep the vertical lines of the building vertical on the negative is to keep the film absolutely vertical also . You can do this by swinging the back of the camera when you tilt it upward . A small but accurate spirit level . mounted on the back of the camera is necessary to tell you when the back is absolutely vertical . If your camera is not equipped with such a spirit level , we strongly recommend that you get one especially designed for this purpose from your camera dealer and mount it on your camera .
HORIZONTAL SWING BACK
This is a camera movement that should be used more often than it is . It has two important purposes . One is to correct exaggerated perspective in a horizontal direction , and the other is to produce an over - all sharp image .
Let us suppose you are called upon to photograph one side of a very long building on a city street . The only way to get it all on the film is to set the camera across the street and slightly to one side , and point it at an angle to the face of the building . This will generally give you quite exaggerated perspective , and the building front will look something like Figure 4. If you swing the back of the camera horizontally so that it is parallel to the front of the building , the horizontal lines of the building will no longer converge and it will be absolutely square as shown in Figure 5 .
The student should note that when the back of the camera is parallel to any object , that object no longer has any perspective . All of it seems to be at the same distance from the observer . If you want a building to appear with its vertical lines vertical and parallel , and its horizontal lines horizontal and parallel , adjust the camera back so that it is absolutely parallel to the face of the building , both vertically and horizontally .
The perspective - less view represented by Figure 5 is not an accurate reproduction , since the building does actually have perspective , even though it may be undesirable to show it for certain purposes . You have distorted the picture in eliminating perspective .
Figure 4 Exaggerated perspective obtained with wide - angle lens when camera is too close to subject .
Figure 5 Perspective of building front has been eliminated by swinging the camera back so it is parallel to building front .
This distortion may not be noticeable to the casual observer , but it can be quite important to an architect . The relationship between vertical and horizontal dimensions have been changed , and the architect will get a completely wrong idea of the relative dimensions of such things as windows , which will seem to be much taller than they really are . If there are any round windows or clocks set into the building , they will become ovals .
It is usually best , therefore , not to eliminate horizontal perspective completely , but to leave enough so that the photograph looks natural . This can be done by swinging the back not quite parallel but only part way to achieve the partially corrected perspective shown in Figure 6 .
The use of the swing back to increase over - all sharpness of the image is illustrated in Figure 7 .
Figure 6 Normal perspective obtained by swinging camera back only partially to get a more natural result than either Figure 4 or 5 .
Figure 7 This figure illustrates how the swing back of a view camera can be used to increase depth of field .
Let us suppose you are photographing some object such as line AB , which is at a considerable angle to the camera . The line ab represents the image on the camera groundglass . However , the point B is at a considerably greater distance from the camera than the point A , so that it would come to focus in front of b , or at b¹ . In order to get all of AB into sharp focus at ab , it will be necessary to stop down the lens . This is the usual way of sharpening the image by increasing depth of field .
There may be times when it is not practical to stop down the lens sufficiently to bring B into sharp focus . In that case , if the back of the camera is swung so that it falls along line ab instead of ab , the image will be sharp throughout and it will not be necessary to stop down the lens . This is an old trick among photographers , and it works very effectively with both vertical and horizontal swings . It cannot be used , however , where perspective must not be changed , since it exaggerates perspective , as explained below .
We have seen that perspective is progressively reduced as the back of the camera is swung until it is parallel to the object . If you refer to Figure 7 , you will see that the new position of the groundglass , ab¹ , is even farther from being parallel to AB than the old position ab . As a result , the perspective is exaggerated even more .
SWING FRONT
The swing front is provided in relatively few cameras , and as a result it is not so widely used as it should be . The swing front is valuable because it permits an increase in depth of field without any effect at all on the image insofar as perspective or distortion are concerned .
As an example , let us suppose you are photographing a very tall building and you have to point the camera upward to get it all in . When you adjust the swing back to a vertical position , you will have some difficulty in getting both top and bottom of the building sharp . To avoid stopping the lens down excessively , you can instead swing the lens until it is approximately the same angle as the film In general , the greatest depth of field is obtained when the front is swung so that it is parallel to the back .
تصوير الخارجيات
تعديلات الكاميرا (الحركات)
CAMERA ADJUSTMENTS ( MOVEMENTS )
In no field of photography is the proper use of the various camera adjustments or movements so important as in architectural photography . The architectural photographer often has to work in very close quarters and it is necessary to resort to various tricks in order to get everything on the film . Fully as important is the requirement that the photographer must not distort the building . An architect or the real estate operator who wants to show a home to a prospective client will insist that the photograph be an accurate , undistorted likeness .
It is surprising how many commercial photographers use view camers without a clear idea of the movements they provide . Because of their importance to the architectural photographer , we will discuss these movements at this point , although the student will do well to remember that they can be used to excellent advantage in all types of photography . The modern commercial photographer who specializes in advertising work uses camera movements to a considerable extent .
RISING FRONT
This is the most commonly used of all movements . It permits you to raise the lens in relation to the film , so that you can get in the tops of tall buildings without the distortion produced when you tilt the camera . ( See Figures 1 , 2 , and 3. )
Figure 1 Skyscraper taken from street level with camera pointed straight forward to keep vertical lines in building from converging toward top . From this position , there is too much foreground and top of building is cut off .
Figure 2 Taken from same viewpoint with camera pointed up to get in all of building . Note that building seems to lean back because verti cal lines converge toward top .
Figure 3 Taken from same position as Figures 1 and 2 , but front of camera was raised to take i in top of building and to cut off most of the foreground .
FALLING FRONT
This permits you to lower the lens in relation to the film . Its principle of operation is the same as the rising front , except that it is used when the camera is at a height and the subject extends considerably below . This condition arises when you photograph a tall building from the roof of a neighboring and somewhat shorter building .
SLIDING FRONT
This is similar to the rising and falling front in operation , the difference being that the lens can be moved to either side .
It is important for the student to note that the use of the rising , falling , or sliding front does not in any way alter the perspective or introduce distortion . Just so the lens is not moved so far in any direction that it no longer covers the film , you can raise , lower , or slide the lens to either side as needed to get the image on the groundglass without giving thought to distortion .
VERTICAL SWING BACK
This is one of the most widely used of all camera movements in architectural photography . If your subject is too tall to be brought into the field of view of the camera , even with the lens raised as far as possible , you have no alternative but to tilt the camera upward . While this will bring the top of the building into the field of view , it will also cause the vertical lines in the building to converge at the top as shown in Figure 2 , which is highly undesirable . You must accept as one of the first principles of architectural photography that all vertical lines in a picture must be photographed as verticals ( except when you introduce perspective distortion purposely to achieve some specific result ) .
The only way to keep the vertical lines of the building vertical on the negative is to keep the film absolutely vertical also . You can do this by swinging the back of the camera when you tilt it upward . A small but accurate spirit level . mounted on the back of the camera is necessary to tell you when the back is absolutely vertical . If your camera is not equipped with such a spirit level , we strongly recommend that you get one especially designed for this purpose from your camera dealer and mount it on your camera .
HORIZONTAL SWING BACK
This is a camera movement that should be used more often than it is . It has two important purposes . One is to correct exaggerated perspective in a horizontal direction , and the other is to produce an over - all sharp image .
Let us suppose you are called upon to photograph one side of a very long building on a city street . The only way to get it all on the film is to set the camera across the street and slightly to one side , and point it at an angle to the face of the building . This will generally give you quite exaggerated perspective , and the building front will look something like Figure 4. If you swing the back of the camera horizontally so that it is parallel to the front of the building , the horizontal lines of the building will no longer converge and it will be absolutely square as shown in Figure 5 .
The student should note that when the back of the camera is parallel to any object , that object no longer has any perspective . All of it seems to be at the same distance from the observer . If you want a building to appear with its vertical lines vertical and parallel , and its horizontal lines horizontal and parallel , adjust the camera back so that it is absolutely parallel to the face of the building , both vertically and horizontally .
The perspective - less view represented by Figure 5 is not an accurate reproduction , since the building does actually have perspective , even though it may be undesirable to show it for certain purposes . You have distorted the picture in eliminating perspective .
Figure 4 Exaggerated perspective obtained with wide - angle lens when camera is too close to subject .
Figure 5 Perspective of building front has been eliminated by swinging the camera back so it is parallel to building front .
This distortion may not be noticeable to the casual observer , but it can be quite important to an architect . The relationship between vertical and horizontal dimensions have been changed , and the architect will get a completely wrong idea of the relative dimensions of such things as windows , which will seem to be much taller than they really are . If there are any round windows or clocks set into the building , they will become ovals .
It is usually best , therefore , not to eliminate horizontal perspective completely , but to leave enough so that the photograph looks natural . This can be done by swinging the back not quite parallel but only part way to achieve the partially corrected perspective shown in Figure 6 .
The use of the swing back to increase over - all sharpness of the image is illustrated in Figure 7 .
Figure 6 Normal perspective obtained by swinging camera back only partially to get a more natural result than either Figure 4 or 5 .
Figure 7 This figure illustrates how the swing back of a view camera can be used to increase depth of field .
Let us suppose you are photographing some object such as line AB , which is at a considerable angle to the camera . The line ab represents the image on the camera groundglass . However , the point B is at a considerably greater distance from the camera than the point A , so that it would come to focus in front of b , or at b¹ . In order to get all of AB into sharp focus at ab , it will be necessary to stop down the lens . This is the usual way of sharpening the image by increasing depth of field .
There may be times when it is not practical to stop down the lens sufficiently to bring B into sharp focus . In that case , if the back of the camera is swung so that it falls along line ab instead of ab , the image will be sharp throughout and it will not be necessary to stop down the lens . This is an old trick among photographers , and it works very effectively with both vertical and horizontal swings . It cannot be used , however , where perspective must not be changed , since it exaggerates perspective , as explained below .
We have seen that perspective is progressively reduced as the back of the camera is swung until it is parallel to the object . If you refer to Figure 7 , you will see that the new position of the groundglass , ab¹ , is even farther from being parallel to AB than the old position ab . As a result , the perspective is exaggerated even more .
SWING FRONT
The swing front is provided in relatively few cameras , and as a result it is not so widely used as it should be . The swing front is valuable because it permits an increase in depth of field without any effect at all on the image insofar as perspective or distortion are concerned .
As an example , let us suppose you are photographing a very tall building and you have to point the camera upward to get it all in . When you adjust the swing back to a vertical position , you will have some difficulty in getting both top and bottom of the building sharp . To avoid stopping the lens down excessively , you can instead swing the lens until it is approximately the same angle as the film In general , the greatest depth of field is obtained when the front is swung so that it is parallel to the back .
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