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.
622. The simplest form of photography, when rightly understood, is hand camera work. But it is a mistake to assume that since it is easy to use a hand camera, it is therefore easy to take successful photographs. One must have a certain amount of skill and knowledge to know even how to press the button rightly, for there are certain fixed laws underlying all branches of photography that must be observed and respected. Neglect of these laws results in failures. With no knowledge of them you are like a boat without a rudder - you are kept guessing all the time. Sometimes you guess right, but more often you guess wrong. Occasionally you may get a good picture, but only by accident, as the chances are against you. Therefore, it is a wise plan to study these laws and be governed by them.
Best Hand Cameras. First of all, what is the best type of hand cameras to choose? As we have seen, some hand cameras have a fixed focus, - i. e., all images beyond a certain distance are in focus with it. In the focusing camera there is an attachment for indicating distances, a scale or pointer arranged outside the camera. The disadvantage of the fixed focus camera is, that no object nearer than the fixed distance can be photographed, while the disadvantage of the focusing camera lies in the difficulty in judging distances accurately. Both these difficulties are overcome by the use of the folding hand camera, fitted with a ground-glass as well as a scale for focusing, for, with this camera, if you are in doubt as to the distance, after setting the camera to the scale, prove the distance by observing the image on the ground-glass. The ground-glass focusing camera can also be used for many purposes that the scale focusing camera cannot be used; therefore, many who purchase cameras prefer one that can be used for all around purposes, and the combined ground-glass and scale focusing camera is, therefore, selected.
How To Test The Focus. The focusing scale on a hand camera is sometimes faulty. To prove this, mark off, along the ground, the distances from the camera as given on the focusing scale. Insert the ground-glass in the camera and set the scale to the nearest distance. If the objects at a similar distance along the ground are not in focus, the scale is not correct. If the object is in focus the scale is correct.
How To Test Camera. Plates are often fogged because the camera is not light-tight. To test this, close the lens, open the back, and throw the focusing cloth over the head and camera. Then hold the camera up to strong light for some seconds and look through it; if any stray light is coming in it will soon be apparent.
The Lens. The most important feature of the hand camera is the lens. The lens is to the camera what the human eye is to the individual. If the eye is poor the sight is blurred; so, if the lens is poor, or limited in its capacity, the picture will lack sharpness, detail and parallelism of lines. It is true that an ordinary cheap rectilinear lens oftentimes will make good pictures of landscapes, marines, interiors, portraits and buildings, under favorable conditions, but when the conditions are not favorable, which is more often the case, the anastigmat lens will be of greater advantage. This lens can be used at a large aperture, which will often save many under-exposures of plates and films, and allow work in a light which with the cheaper lens would be impossible. While a single lens is to be preferred for landscape and marines, it will not take buildings, as it does not render straight lines correctly. Good portrait work requires a special lens. But to take up the question of lenses here is not our purpose, as it can only confuse the beginner. A complete and exhaustive description of lenses and their construction will be found in Volume VI of this Library. For the moment, remember that the difference between a good and poor hand camera oftentimes lies very largely in the lens. If you take up photography with a view to making good pictures and sticking to it until you succeed, then buy at least a good rectilinear lens at the start. You may be sure that it will only be a short time before you will become disgusted with the cheaper lens, and lay it aside to buy a better one. 627. To Test the Lens. - To test the rectilinear lens in any camera, open the shutter, take out the plate holders, and focus on the ground-glass. Cover your head with a focusing cloth. From the picture projected on the ground-glass, the definition and covering power of the lens may be seen at a glance. With a five inch lens at f/8, if we focus on an object 12 ft. away, or set the scale to 12 ft., everything from 8 to 20 feet away will be sharp. This is what is known as depth of focus in the lens. A good anastigmat will cover sharply at open aperture, but distant and near objects will not be defined with equal clearness. The ordinary rectilinear type of lenses has more depth of focus, but lacks in atmosphere.