Early Work In Photography
A Text-book For Beginners

How io Use the Outfit. 69 working with a very small stop, the student will note that he may move the lens back and forth a considerable distance without seriously affecting the definition; thus he becomes able to bring marginal objects into locus, without disturbing the focus of the central ones. We do not intend to attempt to treat photograpliy as an art—that is not within the scope of a simple text-book—but we may mention here that the student will, in the course of his advanced studies, find an enormous field for artistic expression in this power of sup- pressing or accentuating focus, by means of large or small stops. We want our student to learn to secure a perfectly focussed image; when he can do that with certainty, and develop his negatives without stains, dust specks, or blotches, he may wander from this book and turn towards artistic photography. We will suppose that the student has secured a sharply defined image upon the ground glass ; he must now examine the circular level which is (or should be) permanently screwed on the top of the camera near the focussing screen. Tf the bubble is in the centre, all is well, and an exposure may be made. But it is extremely unlikely that the camera nas remained absolutely level while the student has been experimenting with it; therefore it must again be levelled. If, after levelling the camera, the image is still in focus, we may expose a plate. First clamp the camera by tightening the screw which passes through the tripod head, then replace the “ cap ” (or cover) upon the lens so that no light can pass through it; then unfasten the focussing screen and turnit back without shaking the camera. With the same care to avoid shaking the camera, slide the plate holder (numbered “i” and " 2 "), with number " 1” towards the camera, into the grooves made to receive it. When it has engaged with the spring catch it should be covered with the focussing cloth, so that no direct sunlight can have access to the junction between camera and plate holder. With a firm movement, the protecting slide may now be withdrawn, and, when the camera is perfectly steady, the cap may be removed from the lens for sufficient time to properly impress the plate. With regard to the actual time of exposure, there is no absolute rule to guide the be- ginner; all depends upon so many factors. For instance, we have to consider the quality of light, speed of plate (whether “ordinary,” " rapid,” or instantaneous”), size of stop in the lens, and the class of subject; these are all pro- vided for in the commercial “exposure meters.” As we de-