The foreground may be a few shrubs, boulders or large stones, a pool of water, a fallen tree, or almost any object which does not look inappropriate to the rest of the picture. Often a very slight alteration of the position of the camera will enable various objects to he selected for foreground, without changing the middle distance, Or distance to any considerable degree. The middle distance may consist of any of the objects which we have mentioned, and forms the greater part of the picture. Of the distance it may be said that it is only necessary that a very small portion of the picture be occupied by it, although there is no harm in allowing it to cover as much as a third or a fourth of the surface. A small spot of distance, seen, it may he, between the branches of a tree or through a gateway of a stone wall, will just make the difference between a picture and no picture. The finished picture should generally show some sky. This is generally best "printed in" from a separate negative, as will be described hereafter. If, however, there be—when the plate is exposed—clouds which appear to be particularly appropriate to the sub ject, these should be secured. Unfortunately it is seldom that the same plate will secure both clouds and landscape, —exceptions to this rule will be mentioned in connection with instantaneous work,—bceause the exposure which is sufficient to bring out all the necessary detail in the landscape generally over-exposes the clouds, so that no trace of them is to be had. The photographer, there fore, if he wishes to secure the clouds which he sees with a certain landscape first exposes for the landscape, then gives an exposure of about one-fifth as long for the clouds, a second plate being used. These two are used for double printing, which we shall explain hereafter.
Let us suppose we have selected a subject which we think will make a picture. There must be no hurry in the selection of the precise spot from which we are to take it. A few yards to the right or left may, as we indicated before, so alter the foreground as to vastly improve the composition. If now we are working with the most simple of apparatus, as indeed is the best at first, we have only to erect our camera and focus as we described in a former chapter. To use the tripod-stand properly requires a little attention. It should be placed on the ground with its three legs fairly wide apart, and with one leg inclining towards the position of the centre of our proposed picture. Between what then forms the two back legs the operator stands. If his picture be a landscape he may tip up the camera by drawing the front leg towards him. If the picture be of an architectural design, or of such a nature that vertical straight lines are included, the ground glass must be kept in a vertical plane, otherwise the lines will appear in the picture not vertical, but converging either to the top or to the bottom, according as the ground glass has sloped backwards or forwards.
It is here that the various motions which are included in the more expensive class of cameras will be found useful. These motions are chiefly a means of raising or lowering the front of the camera, on to which the lens is attached, and a means of swinging the back,—that is to say, of sloping it either somewhat backwards or some what forwards relatively to the lens. There is also in some cameras a side-swing whereby the back can be swung backwards. We here illustrate the camera which will show these motions.
Let us now return to our manipulations. We have so far selected our view, have planted our camera, and have focussed to such an extent that we can judge somewhat of how much will be visible on our ground glass. We shall generally find that, if the camera be horizontal, there is too much foreground and too little height. If we are not right as regards horizontal direction we simply swing the camera on the screw which attaches it to the tripod top.
To get more height, if there are no vertical lines, we may simply tip up the camera to a moderate extent. If we are taking an architectural subject we must not do so, but must raise the lens, being careful to keep the ground glass of the camera vertical. If we require to take in still more height we must tip up the camera and bring the ground glass once more to the vertical position by the use of the swing-back.
We have so far written on the assumption that we have but one lens for use in landscape work, and that therefore we have no choice as to the amount of subject or width of angle which we can take in.
It is evident, however, that we are very limited in the effects which we can obtain if we have the use of but one lens. It requires but little reflection to show that different subjects subtend very different angles to the eye. To take two typical eases : We require to take the photograph of a large house, but are unable to get very far away from it. It will be evident that the house occupies a very large field of view, or, in other words, subtends a large angle. But suppose, on the other hand, that we wish to photograph a yacht or ship on the sea. We are seldom able to get so near it that it occupies a large field of view. On the contrary it subtends a very small angle, and were our picture to include as wide an angle in the second case as in the first, the result would be that we should see" a long stretch of sea-line with the ship on it showing as a mere speck.
To enable different angles to be included, the photo grapher usually employs several lenses of different focal lenglh,—that is tosay, certain of these are so constructed that the distance will be greater between the lens and the ground glass, which requires the camera to be farther racked out than in the case of others. This we have already explained in the chapter on optics. The greater the focal length of the lens the less will be the angle included, and the larger will appear such objects as are included.