80 HANDBOOK OF PHOTOGRAPHY 



(or bottom) may be moved closer to the lens. It is usually possible to make the same 

 adjustment along a vertical axis. 



If the camera is pointed upward to include in the picture the top of a building or 

 other tall object and if the plate is not maintained parallel to the lines of the building, 

 these lines will seem to converge near the top. This distortion is apparent and not 

 real, because, if the eye is placed at the position of the lens, it will be seen that the 

 lines of the building do converge. In a photograph, however, the viewer does not 

 wish the actual truth but wishes to see the building as he would see it if viewed from 

 a more distant point. 



By combining the use of the rising front and the swing back the lines of the building 

 can be kept parallel. The film should be maintained parallel to the lines of the build- 

 ing by means of the swing back, and the top of the building should be brought into 

 the scene by using the rising front. 



By making use of the swing back it is often possible to bring into sharp focus two 

 objects located at different distances from the camera. If an object near the top 

 of the picture is to be in focus at the same time an object near the bottom is in focus 

 and if the two objects are at different distances from the lens, the edge of the film 



Fig. 8. — By tilting the swing back from vertical position, top and bottom of stairs can be 

 more nearly focused at the same lens position. 



that represents the more distant object should be moved closer to the lens than the 

 edge on which the closer object is to be registered. 



When the swing back and rising front are to be used, the lens of the camera should 

 be able to cover sharply a larger area than the normal size of the sensitive material. 

 In these cases the image at the edge of the film is of importance; therefore the lens 

 must be well corrected and should be used at as small an aperture as the exposure 

 time will permit. 



Removable Lens Board. — View and studio cameras and some folding hand cameras 

 have removable lens boards so that lenses of longer or shorter focal length may be used 

 interchangeably. 



Reversible Back. — Cameras used by advanced amateurs and by professionals have 

 reversible backs so that the picture may be made either with the short or the long 

 dimension of the plate as the bottom of the picture without turning the camera itself. 

 Such cameras do not require a tripod hole on the long dimension of the camera body. 



Other Adjustments. — Occasionally the bed of the camera may be tilted upward or 

 downward; the back may be raised as well as tilted, etc. Such adjustments are useful 

 when making exposures in cramped quarters or when using wide-angle lenses, but in 

 general these adjustments are seldom used. 



CAMERA ACCESSORIES 



View Finders. — The majority of cameras are equipped with view finders by which 

 the user can tell when he has included the required subjects in his scene. View and 

 studio cameras do not usually have such finders. The picture is composed upon a 

 ground-glass screen. 



