VISION AND THE TECHNIQUE OF ART. 5 



with a corrected lens or even with an uncorrected lens. For though the 

 eye has an uncorrected lens, the lack of corrections, so to speak, is 

 markedly different from that existing in any known uncorrected 

 photographic lens, and so produces a different effect. 



To give an understanding of the more specific characteristics of the 

 retinal picture it is necessary to take up and describe the character- 

 istics of the images formed of objects in different parts of the field of 

 view, i.e., the scene at which we are looking. 



We shall take up the images of objects in the various parts of the 

 field of view in the following order: First, the images of objects at 

 which the eye is directly looking, or, in other words, those objects 

 which lie in the line of vision and which are in sharp focus. See A, 

 Figure 1. This will be covered in Chapter I, Distinct Vision. 



Figure 1. Diagram showing positions of various objects in the field of 

 view. F B A C is the axes of vision or line of sight along which the eye is 

 looking. A is the object on which the eye is focused. It will be imaged 

 sharply on the fovea F. B and C are points on the line of sight inside and 

 outside the point of focus. D is an object to one side of the line of sight. It 

 will be imaged on the peripheral part of the retina at G. 



Second, the images of objects which are on the line of vision nearer 

 and farther away than the object in focus (see B and C, Figure 1); 

 Chapter II, Depth of Field Axial. 



Third, the images of objects which are not in the direct line of vision 

 as D, Figure 1. These images will be described in Chapters III, IV 

 andV. 



Chapter III, Depth of Field (Lateral), will deal with the character- 

 istic imaging of objects not in the direct line of vision and at different 

 distances from the eye. See D and H, Figure 1. 



Chapter IV, Distortion in Form, will deal with the distortion of the 

 images of objects not in the direct line of vision. 



Chapter V, Peripheral Color Sensitivity, will deal with the change 

 in the local color of images of objects not in the direct line of vision. 



In Chapter VI the effect of binocular vision will be considered in a 

 general way. 



In Chapter VII the results will be summarized and discussed. 



