"It is often difficult and well-nigh impossible, when using the lens, to get all planes in moderate focus without getting one or some part excessively so, and similarly, if we avoid excessive sharpness in each and every part, some planes, such as the extreme distance or immediate foreground, so broken up as to destroy form and structure. Then it is that the pin-hole, with its equal focus in all planes and at any focal length, seems to recommend itself; but if it be desired to emphasize any object, by introducing more detail there than elsewhere, then the uniform sharpness of the pin-hole image fails us."