This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Fixed Focus Box Cameras Require No Focusing. The fixed focus or box cameras contain no scale. As they are all a fixed general focus, such cameras need no focusing, and whatever is visible in the finder will appear in focus on the plate or film. But with all other folding cameras containing focusing scale or ground-glass, the focus must be obtained by the above method and not in the finder. Use the finder only for locating the view on the plate. Always remember, first, to locate the view in the finder, for whatever is visible in the finder will be registered on the plate. If the camera is pointed at a building and it looks crowded in the finder, then step back farther from the building until good proportions of margin all around are secured. Judge the distance from the object or building and draw out the bellows until the pointer registers opposite the number of feet which is the distance between the camera and the object. The exposure can now be made.
Rising, Falling And Sliding Front. Practically all folding cameras have a rising and falling front, i. e., it is possible to raise and lower the front-board to which the lens is attached. To a certain extent, this feature takes the place of a swing-back or swing-bed. When photographing a building that is not too high and your camera has only the rising and falling front but no swing-back or swing-bed attachment, the camera should remain perfectly level so that the ground-glass will be parallel to the building. To provide more space or sky above the building, or should the building be so high as to make it difficult to get the top of the building on the plate, raise the front-board, to which the lens is attached. Where the camera is fitted with a swing-bed, as well as with a rising front, both should be employed when photographing extremely high buildings.
83. Many folding cameras have, in addition to the rising and falling front, a sliding front, which is of great advantage when working in confined places. It is possible, by moving the sliding front one way or the other, to secure more or less of either side of a view without altering the position or moving the camera whatsoever; but it is very seldom necessary, in fact it is not so convenient in most cases, to use the sliding front as it is to slightly turn the camera on the tripod head.
Swing-Back And Swing-Bed. While all folding cameras are not supplied with swing-backs nor even swing-beds, many have one or the other of these attachments. The following is a brief description of their use:
The swing-back is at the rear of the camera and is so adjusted that it permits the ground-glass to swing perpendicular regardless of the angle at which the camera is tilted.
The swing-bed is simply the front or bed of the folding camera containing the track on which the sliding front moves, and the supporting arms or braces which hold this bed in position are so arranged as to make it possible to adjust the bed to any desired angle, thereby enabling you to admit as much sky or exclude as much foreground as desired. In this way the body of the camera can remain in any position at all times, and the ground-glass will always be perpendicular.
85. The swing-back or the swing-bed should be used when photographing extremely high buildings in order to obtain rectilinear lines. When photographing a high building it is necessary to point the lens upward, and if your instrument is fitted with the swing-back this back must be so adjusted as to keep it in a perpendicular position at all times. On the other hand, if your camera has a swing-bed, the camera itself should at all times remain in the same position (i. e., the ground-glass must always be perpendicular), but the swing-bed can be raised and fastened in position, which will give you exactly the same effect as to operate the swing-back (when the whole camera is pointed upward). Whenever the camera is tipped without any change being made in the position of the ground-glass the lower portion of the building will be nearer to the camera than the top, and the nearer an object is to the camera the larger it will appear on the ground-glass and it is, therefore, quite obvious that the lower portion of the building will appear larger and broader than the top. (See Illustration No. 9.) When pointing the camera upward it is necessary to pull the swing-back out at the bottom, which tips the top of the swing-back toward the building, making the ground-glass parallel to the building, or the object being photographed. Of course, when using an instrument equipped with the swing-bed the ground-glass always remains parallel with the building and this difficulty will not be encountered.