150 Imagination as an Aid to Vision
not. There will be more grey on one part than on another, and both the shade and the position of the grey may vary within wide limits in a very short space of time. One part of the letter may appear grey and the rest black. Certain outlines may be seen better than others, the vertical lines, perhaps, appearing black and the diagonal grey, and vice versa. Again, the black may be changed into brown, yellow, green, or even red, transmutations impossible to the camera. Or there may be spots of color, or of black, on the grey, or on the white openings. There may also be spots of white, or of color, on the black.
When the camera is out of focus the picture which it produces of any object is always slightly larger than the image produced when the focus is correct; but when the eye is out of focus the picture which the mind sees may be either larger or smaller than it normally would be. To one patient the big C at ten feet appeared smaller than at either twenty feet or four inches. To some it appears larger than it actually is at twenty feet, and to others it seems smaller.
When the human eye is out of focus the form of the objects regarded by the patient frequently appears to be distorted, while their location may also appear to change. The image may be doubled, tripled, or still further mul tiplied, and while one object, or part of an object may be multiplied other objects or parts of objects in the field of vision may remain single. The location of these multiple images is sometimes constant and at others subject to continual change. Nothing like this could happen when the camera is out of focus.
If two cameras are out of focus to the same degree, they will take two imperfect pictures exactly alike. If