PHOTOGRAPHING ARCHITECTURE.
the chapter upon the management of the camera no allusion was made to the use of the various mechanical devices with which the camer3 is fitted, the omission being made in order that the mind of the beginner might not be confused by having too many details presented to him. Therefore it now becomes necessary to describe in some detail the use of the swing-back, the rising front, the re versing back, and the different motions with which the camera is fitted. Now, all these movements are most useful and most likely to be required when subjects of an archi tectural nature are attempted, and I shall therefore in the present chapter deal with that most interesting and important subject.
We will assume that the reader has packed up his traps, and has arrived at the place which he desires to photograph, which for the sake of illustration we will suppose to be, in the first place, the exterior of a church. He wishes to obtain a general view and to include the nave and the tower, and ho finds that the only available position from which he can get an uninterrupted view of the whole build ing is from the graveyard, which is bounded by a high wall.
The camera is set up and the subject focussed, but upon examining the image on the ground-glam it will probably be found that instead of getting in all the subject we have only a portion of the nave and about half the tower. The foreground occupying the remainder of the plate. This we might overcome by getting further away from tho church, but that we are prevented from doing by the high boundary wall. The question arises, how can this difficulty be overcome, and the answer is by the employment of a wide-angle lens. It was in contemplation of such obstacles occurring that in the chapter upon lenses I advised the reader, if purchasing a, second lens, to choose one of the wide-angle type. Assuming the advice to have been followed, we unscrew the rapid lens and substitute the wide-angle ono. -Upon again examining the view on the ground-glass we find that now the whole of the subject appears upon the plate, tLe battlements of tho tower being clearly seen against the sky ; but upon more closely examining the picture, \VC notice that the whole of the building appears to be falling over, and the walls of the tower, instead of being parallel, rapidly converge. What is the reason—is this a
defect inherent in the lens ? By no means ; the fault lies in the adjustment of the camera, the back of which, it will be noted, is not parallel with the building, which it must always be in order to preserve the rectilinearity of the lines in the picture. This might be easily remedied by adjusting the tripod until the back of the camera is plane with the building ; but upon again looking at the ground-glass we find that although there is no distortion of the lines, we have, in moving the camera, got an undue amount of foreground in our picture, and completely cut off the top of the tower. The question again arises, Is there any remedy ? Fortunately, there is, and it lies in the proper use of the swing back. We have, therefore, to again tilt the camera upward until we get all the subject on the plate, when, of course, distortion again appears. If we now, however, unscrew the milled heads at the side of the carneta, and move the swing back until it is parallel with tho building, the lines will once more appear free from distortion. But a new difficulty now arises. Before we resorted to the use of the swing back the whole of the picture appeared in fairly good focus ; now, however we may manipulate the pinion, we cannot succeed in getting the whole of the picture sharp. The only remedy for this is to insert a smaller stop, and upon doing so we find that the whole of the image becomes sharp. From this experi ment we learn that when the swing back is used smaller stops (and consequently a longer exposure) will be required. In the foregoing illustration I have endeavoured to explain in a thoroughly practical manner the use and object of the swing back. Those who may desire to learn more on the subject from a theoretical point of view I must refer to more advanced treatises, such as " Abney's Instructions in Photography," which contains an excellent chapter upon the subject. The swing back is also used for bringing different planes of a picture into better general definition, and is largely so used in photographing portraits in the studio. Such use, however, must necessarily introduce a certain amount of distortion, and is therefore to be deprecated.